I believe there is quite a market for the regular Mazda 6. I can't imagine that with hundreds of times more cars on the market than the MS6 that you guys wouldn't have a boatload of parts out there.
As I stated before, you probably should have bought a G37 or a 370Z instead. That would have been more cost-effective than buying a regular 6 and pouring loads of money into it just to beat someone else's car.
I encourage you to figure out why you bought the car and enjoy it for just that. If you don't like not being in first, trade your 6 in on a new Mazdaspeed 3. Then you would have something to at least start from.