Quotes from their page:

"Does JET Performance remove the speed and rev limiters?
It depends on the specific vehicle. On most chips, we eliminate the top speed limiter. The rev limiter is raised when possible and is completely dependent on the application."

( I called Jet and confirmed that the Bonneville chips REMOVE the top speed limiter)

I'll be installing mine this weekend, hopefully.....Thanks, Hector! Saved me some cash on this one. If you're thinking about one of these, get ahold of hector@angryducktofuracing.com or pm 99bonnevilleSE on here. I'll re-post my perfomance data after install this weekend (if it gets here on time!)

I am awaiting the arrival of my supechip. Although it doesn't remove the top speed limiter, it boasts higher HP and torque than JET II. I don't see why you would want to go faster than 120 anyway. Even in racing, I don't get up above 100. I am too scared I would hurt my. I don't wanna crash. Anyway, I will post my findings when I put the chip in the car. I do have a way of testing before and after...thankfully and to the benefit of you guys.

Well.. what they state can easily be covered up.. ( as to why you didn't get 20 hp increase ) it depends on the motor that have it on.. the mods done to the motor.. the outside temp.. humidity.. sea level height to location.. how old the motor is.. blah blah blah.. yadda yadda yadda.. same with car amplifiers... they can boast that the peak power is something wild like 1000 watts but yet the rms is only 150 watts.. woo hoo... buyers beware market.. that'* all.. now that I"ve vented.. I can go back to annoying people here..