well i just saw G4+ #002 is for sale on his site. this is the ultimate Michael, no upgrades needed
as for further upgrades ? depends on your skil level, where you race and how often. as you get better you wil find ways to make the car betterin your eyes. not all the upgrades are needed to make you go fast, some are for reliability issues.
i have found the new G4 duro 2nd gear housing is much better than the stock item on the G4S. has no play in the housing yet, and never have done a spur yet on the G4+. these things are important. specially in a main and your up front or chasing. ask most MTX4 drivers, they seem to strip not long before the finish of a main. very frustrating