I'll point out, the fob on e-bay, amazon, etc. does not even come with electronics. I did get one and with the aid of a dremel, soldering iron, super glue and new battery I was able to cut away the old case replace the battery and reassemble with success.

Forget cutting one and using it, there is zero chance it will work. If you tried that and the vehicle subsequently died, then off the the dealer on a flatbed to fix it, again your only option.

 

@bbyer: Cool...good approach. How much did the ordered cut-key cost ya?

 

I've had keys made in Round Rock, TX by 2 different long-time respected, experienced locksmiths. At the first locksmith, the blank from my new case would operate the door lock but not the ignition. The first locksmith then made a copy using their blank. It worked both the door and the ignition. The first locksmith then compared my 2nd blank (uncut) with their uncut blank and noticed there was a slight indent in the first 1/4 inch of mine. Theirs was straight to the tapered point. They then tried to cut my second blank anyway. It wouldn't work at all and it looked bad to me.
For my third blank (no indent) I went to another locksmith. His initial attempt generated a copy that would work the door but not the ignition. I noticed a slight difference in the profiles between the copy and my original key. I pointed this out to the locksmith (why didn't he notice it?) and after a little regrinding the new key works fine - better than the original!
The lesson is that one must find a really good locksmith but still be proactive!

 

The key blank part number was CWF500011SW for my 2005 LR3. There are two or three slightly different key blanks so do not assume my part number is good on your 3. The dealer will know as long as you provide your serial number.

The cost was about fifty dollars Canadian including cutting in I gathered the UK. This was July of 2011.

I recall it about two months for the cut key to arrive. The story was LR UK was having computer problems with their key cutting machine in the UK and they were shipping defective replacement keys worldwide until they figured out that they had a problem and then determining the solution.

Even though they know me at the dealership, I had to show my vehicle registration to order the key.

For what it is worth, one does not hear too many stories of successful key knockoffs or hoody type guys standing beside a LR for a minute or so and then jumping in and driving away.