Gen2 to Gen3 is night and day difference.
I loved my gen2 but it is a touchy beast at the limit. I tend to push it, IMO why be at the track if you're not. My gen2 saw a few 360s here and there I can tell you and I'm not a slouch driver as a few who've ridden with me can attest to. Once the gen2 breaks you have a nats fart of time to recover, and it can break without warning, like you're on a rail and bam you're swinging out. Again, I loved it but the gen3 is so much easier to drive when pushing it. Now the gen4 is a major step again, although not as much, due to the differetial, the gen4 diff is amazing IMO, I'm comfortable doing Tokyo drift in the gen4 without a beed of sweat. But $ is always the question.
I'd try to at least go gen3. But you'll see as many post the gen2 is the best viper ever made, lol. Having owned them all (except a 5), I love each gen, but for different reasons.