Hi guys, I am just getting back into RC and i'm in the process of getting an RDX Phi. Now seeing as im getting back into it when i left i was running stock (about 2 yr ago) so i need to brush up on my driving etc. I will be running it in 540 for now cause i don't have the funds for stock just yet. So my question is do i need to modify the motor mount to fit big pinions so i can run a ratio of 4.2? Or can you run aftermarket spur gears on the car so i can just get a real small one?