not alot but i have a 2004 gtp with 3.6 mps speed daddy headers and slp exhaust with cai. im sure a gtp with these mods will exceed 100 mph maybe not 100 with in the 1/4 mile but close enought to worry about my limiter because it cuts out at 96 and today it went up to 98 for some reaseon but i ran it a couple more and verified that at 96 mph it starts to cut out and it feels like your hitting the break. i found a thread about this some where but cant remeber been along time ago.