From previous experience:
Great rivalries:
BMW M5 vs. Dodge Viper SRT10
I've tested these two babies against each other in the race reports section twice. Those of you who've read my article on the BMW at the Nur and Supercars at the Autumn Ring know I've picked the Beemer. The Viper might be faster in the right hands, but then again, it might not. I'd like to see what you guys can get out of these two 500hp behemoths.
Corvette Z06 vs. Tuscan Speed 6
Both entertaining, both around 400 hp (or a little less), both crude in some ways, spectacular in others and incredibly fast for the money (
live4speed, where areee you?

) both long and sleek, and they turn in similar laptimes. I picked the Tuscan in GT3 (did a zillion laps in both), but in GT4, I'm a little more inclined towards the Corvette.
GT-One vs. R390
Let the fanboys fight over it. What ruins this rivalry in GT4 is the absence of the spectacular GT-One Road Car. If it was still there, the Toyota would win... probably.
Interesting rivalries:
Alfa Romeo GT vs. Mazda RX8 as per
AutoCar
Both nice cars, the Alfa is definitely one of the best FFs you can buy, while the RX8 is a good, medium powered FR. I'll have to give this a schwing.
Alpine vs. BMW 2002ti as per
Monty's post.
Both great, dynamic and tail-happy little cars, no other two cars could be so different underneath, but still achieve the same fun result. I'd score this a tie, as I honestly can't pick between the two.
Aston Martin DB9 vs. Jaguar XKR
These are the closest to each other in terms of price and mission, but I think it's unfair to compare the old XKR to the new Aston (old DB7 would be closer).
Mitsubishi Eclipse GT 06 vs. Nissan 350Z
It's a closer match in actual power than the 350Z vs. RX-8 one. The Mitsubishi is definitely nowhere near as fast, but it's very fast for an FF car, and will endlessly entertain on a twisty and bumpy track. They're both big V6 coupes with a heritage, both started out as small, simple boy-racer dream cars, evolved into bloated cruisers, got killed off, then got reincarnated as heavy V6 sports coupes with great dynamics. I don't know which is better, honestly, but if it's a race track, I'd pick the Z as the better car, and if it's a road track, I'd pick the Eclipse as the bigger hooligan.
I'm full of them... this could spark off something once I finish my current series.
