LRDBlaster, you couldn't be more wrong. You can easily get 5 hp by just
"cleaning up" the terrible casting that yamaha does on the BANSHEE jugs. Every set of stock jugs I have had the pleasure of taking a look inside had the sleeves misaligned, high seams everywhere, nuggets of aluminum hanging down into the passages, and every other manner of bad workmanship. The power you can get out of correcting these problems is astonishing and anyone with any knowledge of how a two stroke works can EASILY perform this mod. This will not affect the motor negitively in any way. It will give you virtually FREE horsepower.(minus the grinding bits) If you buy a banshee that is stock, this is one of the first things you should do to your motor. If you need more power, get a port kit. You can easily get 15 hp out of the sportport, without even messing with the transfers.
If you are into being able to say that the engine you have was ported by "dan, mike, joe or suzy", get it done at a shop.
As for me, I can claim that I did the work. Win lose or draw, it's my baby. You will gain so much knowledge by doing your own porting it will blow your mind. Never again will you pay someone to work on your "Baby".
DIY, then charge all your riding buddys $200 to port theirs. You know they will want to keep up with you after you smoke em'