My home is in Worcester, MA and I work in Natick, MA (well, till I'm officially laid off the end of next month
).
My bike is a 2003 Busa with the mods listed below. I upgraded from a 2001 Katana 750 and have been riding for over 6 years now with ~15k miles under my belt in total (just over 1400 on the Busa now).
I purchased my Busa from Sky Cycles in Lunenburg (quite a trek from both Worcester and Woburn). They gave a good deal giving me $150 off the MSRP and only a $50 setup fee (most shops around Worcester were $200-$300 and nothing off the MSRP). I recommend Sky Cycles for the purchase, the service can be done at any dealer tho, so don't feel pressured to have to go all the way back out there if you pick one up from them.
As you are upgrading from an older bike, be sure that you are confident enough to handle the Busa... my upgrade was over double the HP with a minimal weight increase. I could handle it and am still surprised at how easy it is to handle considering it's power.
I have no suggestions as to what to look for / watch out for on a used Busa.. that information I'm sure others can supply from this board. I purchased new so I didn't have to worry about it.
Good luck, I love the Busa and you will too if you decide to get one!