As far as the sport machines... The 450's are pretty even stock for stock. Put the $30 Cherry Bomb from Yoshi and a pipe and it will leave a piped honda...BAD. Put a new exhaust intake and jetted properly it will be even again. No other machine responds to upgrades like TRX450. With a GT Thunder rear linkage, steering stabilizer and dialed in shocks, the 47" wide can take turns just as fast as the 49.5" wide LT-R.
In the 400 class, the EX is the ultimate trail machine. The EX has much better acceleration but the Z has better top speed. The Z is more track built and the EX is more trail built.
Thank you to my 2012 Sponsors:
Dynamic Graphics, Inc.