I do not know what you did inside the tranny so i wont comment on that but your cars not going to trap higher you're deep into the rev limiter at the lights. So don't expect better mph unless you get taller tires or turn the limiter up. As for the tranny i'm betting it still has the blockers and stock dogs in it. It's decaying so if it twer me I'm have gforce or someone go thru it and do a face plate mod to it for faster shifts.. Impressive little car for the altitude, but that stock tranny needs some love and longer gears wont do you a bit of good if 4th is 1 to 1 like this tranny is.