yup, try before you buy.

It also depends a lot on the gun you are starting with... if the base gun is a MK2 Tx200, or an HW99S, there is much less room for improvment than with say an HW80, or any of the big Dianas.

Also consider the middle choice, of fitting a professional tuning kit (e.g. from Tinbum)...

Rgds,
JB