According to Matt:
Believe it or not the chassis is almost totally stock, except for a few specific mods; The chassis. That is obvious. Another modded item is the center driveshaft. That shaft resonates HORRIBLY above a certain RPM. I modded my shaft by cutting the center of the shaft out (leaving only about 2 inches of each end) and made a sleeve out of K&S aluminum tube that was epoxied to the shaft ends. That gave me a hollow, large diameter, center driveshaft. That cured the resonation problem. Another important item is the rear toe-in. I used a suspension pivot mount from the front of the car on the rear (in front of the rear diff housing). This netted 1/4 degree rear toe-in rather than the 2.5 degree it came with. This gives far less rolling resistance and much better rear tire life. The motor mount is another obvious hand machined item.
Beyond that, the chassis is totally stock. I am even running the stock differentials with no problem. The car has seen 3HP at 80 ounces with no driveline problems. However, the latest incarnation (which hasn't run yet) is 90 ounces at 4.3 HP. I am not sure if the drivetrain will handle it. I hope so. Honestly, wheel spin is a decent clutching system to help the drive train survive.
Wait till you see the new setup! I am not giving away anything just yet, but it is very cool indeed!
Oh, it must be noted, I am not out to break the world record, per-se. I am trying to build the fastest, highest technology daily driveable street car possible. That means it will be very fast indeed. But, this car is not a dedicated top speed only car.
Think, Bugatti Veyron.