Talk 1520 - your experiences

[RC-Monster Mike]

IMO, the 1518 is waaay more motor than a buggy needs and plenty for all but the porkiest trucks. The 1520 is plain overkill unless you have a 15lb truck with big aluminum rims or something.
Jahay -an idler gear doesn't add any speed or take any away - it is simply there to create space(usually to allow proper gear mesh with a larger diameter motor or small spur gear) and it reverses the direction or rotation(as far as the gear ratio goes...it is "idle"). :)