Upgrade single amp or bi-amp

I have been thinking of upgrading my Acurus A200 which is currently used to drive my Magnepan 1.6. I know there are many high quality amps out there for my Maggies such as Stratos, Belles, Bryston, etc. Given that I do have a budget limitation in mind and just about any of these better amp will cost twice or three time my A200, would it be better if I just buy another A200 to bi-amp instead of upgrading to a better single amp that cost twice as much?

I've always been a fan of biamping personally, but it is always the best idea to listen to the combination before buying. If you can get a bryston or a Stratos on loan for a night or two, I would try that. You already know the characteristics of the A200, and I would guess that biamping would produce the same characteristics, but the sound may be more dynamic, more conrolled bass, that sort of thing. The best advice I can give is just buy what sounds right to your ears.
Hi Spud; passive vertical bi-amping didn't do much for me with a pair of McCormack DNA2 Rev. A(s), and I now use a single Rev. A. I can't speak for Acurus upgrades, but McCormack upgrades are excellent. I understand active bi-amping can produce worthwhile results though-- with a good active cross over-- but your speakers have to be able to accomodate this. Good Luck. Craig