I had this same debarcle
In the end I decided to stay with the 26 they rev harder everything bolts together and it cost a lot less to build
So I ended up with oversized pistons that bring it up to 2.7 litre and brand the comp up to a nice 9.1 on e85 should be a weapon
The point is if yours aint broke dont throw 10 or 7k at it to fix it its alreay making good power and response as u said work on the setup if u want more or made striping the shell for less weight, light weight wheels better brakes and suspension there is a lot more to a track car than outright power
And if you get serious you might be not allowed in some events for changing the L size from factory ?? I am not sure someone else mabe can conform this