I've taken my car to around 162 when it actually stopped and started to slow to top out at 131mph. I found out later I had blown a spark plug. I thougt the Turbo was dead. But the turbo has nothing to do with Top Speed. It just gets u there much faster. I've raced cars from Mustangs, to Suped up Eclipse and Accords with only 5 spark plugs. Still left them in the dust. I changed the plugs and so i'm taking on Vipers and Vettes again. Looking to upgrade to a stage "3" mod for my 911. That will give me about 500hp with a dual Turbo. 0-60 should rocket me into the 3.9 range. i can hit 0-60 now after service in about 4.5 second range.