RE: How far can I push it?
There are quite a few things you can do to a Shuttle without spending lots of $$$
1) Increase your servo outputs as far as you can go without causing any binding at the swashplate. If your pivot balls are at 8mm from center, go to 12.5 as an example.
2) Set up a stunt curve. This can be done a number of ways. Give me a call at 732 225 6144 ext 230 to discuss.
3) Run lighter paddles on the Flybar.
4) Get some FRP or Carbon Blades. Woodblades are not ideal for aerobatics
5) You might want to consider adding a BB or two here and there as well. I have done piro flips with a Shuttle Plus, basically like a Z but more recent, but would probably need to replace the bushings after some time.
But for basic loops rolls etc, the Z is more than capable to do that.
If you have any questions, give me a call, more than happy to help.
Jeff