Sticking with the old 450 SA, I'd say go to HeliFreak.com and snag a used gyro over there. I bought 2 Align 750 gyros used from there and both are AWSOME. (one was $75 shipped the other $80) One for my 450 Pro and one for my 500. Both helis are Trex clones but I love them. The 450 Pro is solid and very very stable. Nothing like my old HDX450SE v4. Difference of night and day between the two. As for buying a new super combo I'd have to say the 450 Pro Belt version. I've heard nothing but good things about the TT version but they say it cost more in a crash to repair. All in all I'd say if parts are still around for the 450 SA then stick with what you already have, just upgrade the gyro and even spend the money on a new motor. Hope this helps. Joe