996 C4S Chipping / Remapping

[thesnug]

Have any of you guys any experiences of this?
I have a stock 04 C4S with sports exhaust which has been the ultimate car of my dreams, and she is a Babe. But I am wondering whether I could (should?) tweak a few more horses out by fitting a superchip or similar. My big worry is ruining an already sublime car in the pursuit of a bit more grunt and also invalidating the warranty. Also, can anyone recommend an independent Porsche Service garage down here in Somerset? Many Thanks