Clip, did your sandstorm come with a .21 or a .18? If it was an .18, you'll need a few parts before you can bolt in the .28.

As far as someone saying that an engine has more horsepower, or WILL have horsepower because it has more ports... that's not true! It is all in how the ports are designed Example, the OS V-Spec (a 3 port) has an incredible amount of power compared to the SH .21 8 or even 9 port.

This is just advice, I'd steer clear of Axial engines. The price is tempting, and there is a reason why it IS that low. Personally, I'd go for the sport .28 engine that Go Tech has to offer. Amain has the non-pullstart variant, they might be able to get you a pullstart version