Can't say anything more on the real word way of correcting it as zak's said everything i would've (and a fair bit more aswell) It can be fixed in GT3 though to handle perfectly, i've got a 540bhp evo 6 that doesn't oversteer at all without applying the handbrake it all depends on how you've got it set up.
btw Zak, in gt3 if you don't pay for it you don't get an lsd in the mx5 iirc.