How does the front bumper come off/get disassembled on the XKRS? I need to do some paint touch ups and need to know the right way to take it off without destroying parts. Is there instructions or explanations anywhere?

Yes. the workshop manual clearly lays out the step by step procedure. You can download it from the stickies in this forum.

Is it the same as the XKR manual? I couldn't find one for the XKRS.

Microscopic differences between all models.

Isn't the XKRS pretty significantly different in both body and engine?

No. A little different trim and a slight tuning difference in the software (I flashed the -S engine tune to my XKR, took about ten minutes). If you go to the XKR-S GT, THAT has a bit more, but mostly just suspension and steering added to the -S, plus extra added aero.

Follow up question.

How do I get the side trim pieces off? I got the cover off and it looks like they're held in with two attachments (not counting the screws at the bottom), one is a click in and slide, the other one looks like a weird plastic piece that snaps or screws in, but I can't see any way to unscrew it. Is that some sort of clip I can just pull out on the outside?

Pics below