We're putting together our first 'non-trainer' plane, which is Top Flite's P-51D Gold Edition Mustang. (It's not the giant ed., it's the one with a 65" wingspan." It came with an OS .61FX engine. We're thinking, however, about upgrading engine size - perhaps an OS.91FX. On the other hand, we're wondering if we should go up to a 4 stroke, and get a 90 4 stroke, for example. Only thing is $200's the limit. With this range, it appears that we could go with an OS .91FX 2 cycle or we could go with a 'Magnum' 4 stroke 91 engine. Or, we could simply stay with the .61.

Any recommendations / advice would be greatly appreciated.

Thanks,
Joe