I currently have a 1/8 buggy roller with a castle 2650kv motor. Will run it on 3s or 4s lipo. Any recommendations on speed controller.

120 amp vs 150 vs 200. What do I really need? Or how should I choose for that motor/battery setup.

note: this will be used mostly for bashing, backyard track racing. Looking to stay budget minded.

ESC?? Both Tekins RX8 and Castle Mamba X2 are Ferrari, Lambo, Bugatti, and Ford. Castle does say specs on the ESC, Tekins does at 300amps. expensive ESC. You want buget ESC? Hobby Wing. Chevy to Kia comparison, But still competative between all 3 products.

Just buy any cheap RTR ESC from Jennys RC or something like that.

A lower amp ESC will probably offer less punch and run hotter.

I disagree on the blanket statement that Tekin or Castle is better then Hobby Wing. It's all in the application and the model. There are certainly cheap HW escs that have fewer features, but will work fine for bashing and backyard fun. However, their XR8 Plus and Pro are just as good as anything out there for racing.

Ended up going with a used rx8, what gauge wires should I go with, and are deans plugs fine to battery?

^12 AWG and deans are a little on the weak side imo. Use something bullet based like an XT90, whatever ARRMA uses, etc...

Okay thanks