Alright..yay..lets start another which stock tuner is best thread..
ROAR X is good on larger tracks, or flowing tracks, but it's hard to beat the CO27 when you can just keep gearing it lower and lower. Most tracks a properly geared CO27 will have more rip out of the corners, AND have high end RPM. ... Regardless of who tuned it.
But if the cars never really have to slow down and you can keep a ROAR X in it's sweet spot, it's a very good motor.