I think amainhobbies.com is probably the top site people use.
I have a history much like yours (Tamiya Wild One, Gold Pan RC10, etc.) and I am still learning on the 8ight 2.0. I found that AKA City Blocks in Super Soft really helped my car a lot. My car was almost un-drivable with Proline Crimefighters (Soft). people keep saying that with more break in time the car will get easier to drive. My Ten-T is so easy to drive compared to this 8ight!
Also for the shock mod, you might want to wait and just buy the vented shock caps that were released with the 8ight EU. Since you will want aluminum caps anyway, you might as well buy them pre-drilled. You can then buy the foams from Losi, or make them yourself.
Part numbers for both are: LOSA5422 & LOSA5431
I am not sure if these have been released in the US yet. If not, they will hit the streets any day now. (Edit: They are being released "Mid-April" according to the Horizon website.)