Before GT5 I played DiRT 3 a lot, I still do to a state. To get a car to act the same in GT5 as it does in D3 would be tricky due to D3's sudo-realistic physics. You could only try using a 4WD car as the RWD cars in D3 act very similar to 4WD. If it is possible to tune the car in hte right way, your best bet would be the Evo X. For the tune I suggest full parts (except use a stage 1 or 2 turbo) and rear wing. Tyres would be CH or more likely CM. Give the car a stiffer suspension setup and tune it from there. As for LSD, Try something 15-30-30 or 5-15-15 for front and back. Just fiddle around until it feels right