Look around. More people are using the Evo 4 and Evo 5, because it is simply better.

if you think the Evo VI is fast and you like the car, then stick with it. The Evo Vi has three good tracks- Iro, Tsuchisaka (the last track) and Akina Snow. The Evo III is great on Iro, Akina Snow, Akagi..so i can't see how it's the worst Evo. The Evo IV is practically rules Iro, Tsuchisaka (Evo V slightly better here) and Akina Snow while the Evo VII's only real good track is Akina Snow. The Evo VII is also decent on uphill tracks.
Just take a look at the internet rankings (
http://ranking.segarosso.com/inidas3/n1_rankparm.php) and you'll know what i mean. Don't go by 'oh you feel the car is fast'. It might not be the case. FEEL and FACT are different things. I'm not saying the Evo VI is crap, it's just simplay not the best Evo, and that's sad, because there is no way the Evo IV and V is better than it in real-life. Hope i have cleared up all queries. I have put up the facts, given you all the internet rankings, it's up to you to figure out what you want.