I have COMP cams in my cobra and I absolutely LOVE them.
I swapped them in while I was putting on 03 heads, so it really wasn't any extra hassle for me, since I had to pull the engine regardless. Also I found them at a steal so I couldn't say no.
Anyways, while I do not know how much power I picked up from the cams alone...with stock 03 heads, stock 01 intake, and COMP #106400 cams, my car laid down 326rwhp with my ONLY bolt-on being an o/r x-pipe.
I got my car into the 370-380rwhp range by adding bolt ons and I am absolutely in love with hard the car pulls...with 3.27s it pulls hard ALL the way to the fuel cut off @ 7100rpms and still trapped 113-114mph all day long with the crappy 3.27s, 18" saleen replicas, and stock shifter.
The sound of my car at idle AND wot makes it worth every single penny.