None realy. The 12-hole box mod is out 100%. Opening up the exhaust will drop the engine's ability to scavenge which will effect the bottom end. And the electric fuel pump is only needed if the stock pump fails. Just tune it properly...with the proper jets for your altitude is the best thing you can do.Ok thank’s, both mod is not a good set-up.
So Which option will be the best.
I open the exause all ready. ( i still have a stock one)
12 holes air box.
Adding a electric pump and keep stock air box.