hooooookay then.
First off 13:1 is a high SPEED set of gears not high TORQUE. What you actually want is a high torque MOTOR (ZCI, SHS, Lonex) coupled with high speed gears (ZCI, SHS Supershooter, Siegetek) or just an out and out high speed setup. High torque gearboxes are built to pull big springs for high FPS and generally aren't terribly "snappy".
If you're looking to improve your trigger response then a Mosfet - hardwired not plug and play - is the easiest way to do this. If you're planning on running an 11.1v LiPo then it's a must to stop you burning out your trigger contacts.
AoE correction using sorbo pads will help quieten your gearbox, also look at a Lonex POM piston head.
Trigger pull - http://www.fire-support.co.uk/product/speed-m4-blade-trigger-silver OR just fit a BTC mosfet that replaces the trigger contact block.
While you're at it, get a set of shims because the gears you fit will not fit the same as the gears you take out.