ok, you dont have to use the Lola VDS body it comes with, you can put a sedan body on it if you want, but you will want the sedan conversion kit and a front bumper (less than $20)
i would have to say that the max MPH on the G4 LeMans RTR is around 60+ mph, but thats just a guess.
its pretty damn fast, though.
another alternative is the G4S RTR kit.
It will come with a sedan body and all the components are race legal.
now, as far as your previous post, regarding the car for sale on ebay
i'll say this; you get what you pay for.
a car that costs $149 shipped, is going to perform like car that costs $149 shipped.
there are no upgradeable parts on that thing, save custom fabricated and as far as support after you buy it...
stick with something that will last you a long time, is designed to be upgraded and has proven itself on the racetrack as a performer.
my suggestion is to go with the G4S RTR, for $425 shipped, its an outstanding deal, I can personally vouch for Sam, who will treat you right and take care of any questions or problems you might have and he will be there after you buy it to offer advice and hop up parts.
hope this helps.
check that out, its actually an amazing deal.