Everything is a trade off. If you go longer it will not turn as easy. The longer it is the harder it is to hook up with common tires you will want to run on the street. The longer you go the more likely you are going to run into hitting the rear tail. The longer it is the more of a need for different shocks and spring rates to hook it up.
64-65” wheelbase base busa are pretty common, but I agree with the above post, I felt 61-62” was a better all around combination. I wanted to keep the stock “more stealth” look so I went with a 3-4 McIntosh. It does not have the 6” long slot that looks a bit out of place to me. With the shock, I could hook it up at the track pretty good with a Pilot Power. It stuck like glue with more race oriented tires.
A 61-62” bike will take more finesse to launch than a 64-65” bike so there is a bit of loss on the 60’ times with the shorter bike. It will still work better than a stock wheelbase regardless.