Welcome, I am seconding what the above guys said. here is definitely a great place to start. Everyone is really nice, and know a lot about xmods do-s and dont's.
to answer your question what I recommend.
is if your intrested in the trucks, snag a AWD kit for your truck. One of the "must-haves" in almost all xmods. it enables you to tackle more obstacles, and allows the "drifting" skill to come a lot easier. (for cars at least)
suspension is always nice too.
If you want to chase that cat around quite a bit? I suggest investing in some rechargeable batteries. radioshack sells a $29.99 pack that comes with a charger, 4 AAA batteries, 4 AA batteries, and a car-to-charger wire. fully charges batteries in "1-2 hours" but I think its faster.
Hope that helps, and if you really start getting into this stuff, then there are much more you can do
