I realize this is an old thread, but I've recently revisited the flip key mod. I have a case that has a little pocket next to where the key pivot is, and after going through the thread it sounds like the transponder doesn't need any power. I have two regular remote keys (let's call them key #1 and key #2) and the valet key, so to avoid any soldering, would I be able to just get the flip case, take the transponder off of key #2 and use the remote of key #1 with the transponder from key #2 simply tucked into the flip case?
I already have some 30ga wire on order, but if I don't need to do anything more than use my soldering iron to remove the transponder, then I'd rather go that route. I don't mind being left with just one working remote key and a valet key.