I also have a P400 and have felt zero lag or hesitation at any RPM range. I test drove the P300 and P400 each overnight before I bought one, and the clear winner for me at least was the 400.

 

Another worthy point to mention between the P300 & P400 is the axle gear ratio

P300 4.11
P400 3.73

There won't be much difference in crawling or steep hills.
Bigger tires need higher gear ratio, the P300 got that covered better than the P400.
Combine that ​with 220 lbs less engine weight.

​​​​​When I ordered my 90 P300 I was very keen on the overall weight, 4720 lbs / 2140 Kg ( full tank + driver),
But I did order the S spec, with Airsuspension + E-diff + Console + elec.seats, etc which add another 200 lbs / 90 Kg

 

Gear ratio is not a useful comparison between engines with different outputs. Torque at the wheels is what matters.

 

Many others will not agree with me but I wanted to share my thoughts. So please take this as a friendly comment. If you have no time then this is it.
I love Defender p300 it feels I am driving a special car even with 4 cylinder. The design, ride position, and quality... very nice. No regrets on the engine choice. I think the new Defender is one of best SUV in today's market when you consider money paid and what you get no matter which engine and trim you go with. Now if you have time then read below.

I have a 2023 P300S with 4K miles now. S trim with off-road pack and air suspension with 19s. The reason I bought this car is the name 'Defender'. It tells you everything This is a off roader! I will be using it for some off-road/road trips as well as some daily driving. GUYS u need to understand that this is a Defender not a Range Rover line ups. Even with this new monocoque body and tons of aluminum, this car will never be par with fast SUV options like x5 or cayenne. This is a heavy tall SUV even with lightest engine option 4 cylinder. So I do not understand why the engine option matters too much here. p400 0-60 is 6 seconds... 6 sec is not fast but a okay in 2023 for SUVs. If you want a fast powerful option then I will definitely go with the V8 but again why a fast Defender? Only reason I went with p300 is easier repair under the hood being a 4 cylinder especially without the complicated mild hybrid set up. I have a spare car and not intend to sell my Defender at all. I personally will never buy this car if I was looking for my main transportation hoping to put over 100,000 miles like you do on toyota/lexus. My approach was a decent off-roader without too much money spent on suspension set up for off-roading. I ended up spending good amount of money on 2020 GX460 for suspension mods but I was tired of the horrible ride quality with the lifts. So my option was the new Defender with air suspension. 300hp and torque is enough for most off-road situations.

The fact is Defender is not for fast fun driving or comfort SUV. If you want all that then I recommend a BMW or Porsche. If money matters then do not buy LR and RR products. Moreover, the mpg on this cheapest 4 cylinder p300 is not even good (16-17 mpg combined). So do not buy p300 to save money.

My experience on p300 in short. I had x5m before my p300 but I never felt p300 is under power. It is well built and packaged but it is not a fast SUV you are looking for. However, this p300 4 cylinder engine is not like other 4 bangers. It manages to pull the power you need from the low rpm so much better experience then other 4 cylinders. NO jurks that I experienced from other 4 cylinders. However, the p400 is better in all corners then p300. p400 is more powered, more comfort. and I think better with MPG (p300 uses its engine to the max on highway) The wind noise is worst of my previous cars. It is worst then my friend's G wagon. The back up camera is so dark can't see much at night. Interior is very useful but it will not be luxurious even with the carpathian edition. The design is not just meant for comfort and luxury. The rear seats are not comfort. Trunk is not big. So overall this is not a good family SUV. Also, I already experienced some issues below... So this is not a reliable option you want.

Engine stalls when in 'D' with autohold stopping at red light. The engine stalls out when I step on the accel pedal. This was horrible experience but was fixed with a software update.
Center screen goes black or freeze. This happened twice but was gone after a reset.

I think there is only two reasons buying the new Defender. Design and off-road capability. So my bottom line is as below.

If money don't matter and will not off-road then go with Carpathian edition except if you want different color options.
If you are not off-roading and want a cool look then p400 x dynamic
If you are a hard off-roader then p400 base or a JEEP WRANGLER
If you want daily and some off-road then p300S
If you want pure off-roader then p300 base (wish we had diesel option)
If you are not considering any off-road and getting Defender without off-road pack then do not buy Defender. This is not what you are looking for. You will regret your purchase for sure and I think any Defender without the off-road pack will not be attractive when you try to sell it.
If you want a reliable car then don't buy LR/RR period. I am not saying they are bad but all the line ups have too much tech. You need to go with like a 4 runner but they lack so much areas.

 

My 2022 build has 7 seats with the P300 S. There was no issues for me to build/order it this way. Even with 7 passengers plus a full roof box on a 800km mountainous trek, I was never left wanting for the power I needed.

 

Have 6k miles on my P300 and am very pleased. There are moments when you know its underpowered but keyword her is moments and the price difference is huge. I had people test drive the car without knowing the engine size and they all thought it was a 6-cylinder.

My only comment - and this may not be related to the engine itself - is that I've noticed the transmission to be laggy especially at low speeds/low RPMs and its jumpy sometimes. I dont know if the transmission/gear shifts are related to the actual engine but something that I would argue plays a more noticeable difference as opposed to actual engine size so pay attention to that.

 

I'm a Hard and Pure off-roader. Perhaps a P350?

 

Just a quick question as I too am getting ready to place an order and am mulling over the 2 engines. Well, mulling over the price difference to be more exact.

I did drive a p300 briefly around town and was surprised that I found the power to be adequate around town, no problems there but can you drive the engine at 80-90 mph on the highway without over stressing the engine?
Say like on car trips doing 80-90 all day long or is it a little much?
Thanks

 

Another thing to keep in mind between the 2 engines would be towing. If you're planning on towing something bigger, the P400 will definitely come in handy.

 

That's interesting. When I ordered mine and was on the builder in May 21, the addition of the third row immediately bumped it to an SE and the P400.

I have never doubted the P300 has more than enough ooomph for the seven seater. I spent a lot of time on the website-builder doing various trims and specs. I knew it back to front and inside out back then. It certainly made no sense to insist upon the P400 with 7 seats me other than a $$$ grab. That was certainly the way it was for me. It also automatically added the 3 zone climate as part of the family pack which I could have done without.

No dogs ride back there and I couldn't care less if the third row kids are a bit too hot or cold.

I'll survive and grumble along in my P400, wondering what might've been.