well ive got the pure ten alpha with the two speed transmission on my gx12 and its much faster compared to the standard transmission. I would totally recomend it , together with a more powerfull engine .15 -.18 size !. Prons: acceleration , top speed reduced heat coming from the engine . Cons: NONE.
Where do you find parts for your car? its hard to find for me , as it is an old car. Do you have a tuned pipe on your gx12?
I ve put on mine full ball bearings and it accelerates even faster.Also im thinking of changing my engine it is pretty good yet old and underpowered . Maybe the Lrp .18 prospec3 Ive heard its one of the best for its price.
Show us some pictures of your car.