Harmon Kardon are the top of the line audio system for Landrover discovery. Mercedes also use the same brand. Im not sure which line of LR Discovery's have those. HSE7 and Westminster Editions have them. SE have the basic Alpine audio as far as I know.

 

Having the HK audio option just means you have more speakers to deal with. And with the age of these trucks, they're well-worn. Case in point, my truck has the Harmon Kardon system and the smaller front door speakers are blown out. Rear subs are blatty, too. Replacing them all with quality aftermarket units would be night and day, for sure, but that's going to get pricey.

 

Unless you have an S, SE, or LE, you have the same number of speakers in an SE as the HK system.
I assume you have the Phillips in your SE. The HK amp should provide more power. I replaced my Phillips amp with the HK amp, and ended up replacing the rear door subs shortly after. Almost too much power on the highest bass setting.
I haven't changed out the door speakers yet, but they're probably slightly better.

 

They are just old paper speakers, man. If I was to go through the trouble of swapping speakers I’d just buy some new ones ( any brand, I did pioneer).

 

The HK speakers are almost identical to the Phillips High Line. It's not worth upgrading the speakers to the HK units. The HK amp may be worth the effort to upgrade. I'd like to hear from others if it's a worthy upgrade also.