Leather seats shouldn't be a problem, though I haven't looked at them personally. I've done this same sort of install on a 02 Nissan Altima with leather, and had to take the leather covers off my 04 RX8 to fix a broken wire. I didn't pull them all the way off, just took off the back/bottom so I could slide the pad in. Like stuffing an envelope.
As for the metal rings holding the leather on, you can replace them with heavy duty zip ties. I did this in my Altima and they were trouble free for the 4 years I had it.