It is of my opinion that the stock pipe is too restrictive to allow the revs and the FMF pipe with your stock silencer will give you the rev you are looking for. After that the carb bore will probably get you even more. I have the FMF pipe and Boyesen reeds on my 220 and I really like it.
Ya the carb bore, reeds and a modified air box lid will let it rev a bit higher but the fix is going to be installing an aftermarket pipe. If you are looking for more pull on top with out giving up any bottom end then the rev pipe is likely what you're after. The design of the stock pipe is poor at best and as you've noticed they fall flat on top long before they should. There is lots of usable power to be had and retaining the stock silencer keeps it super quite.
If you have the chance give a 220 with a pipe a try and see how you like it, they are still very friendly.