the RX8 I beleive fits fine.

Larger ESCs like the Viper VTX8 its VERY VERY close to the motor sensor wire. If you had say a motor that had the wire slot from the front solder post area versus from the top would be fine I think.

But, I have found when I used the Tekin 1900 and the Viper 1900 they were more than enough motor for the track. Tekin doesn't recommend there motors , the buggy ones, for truggy usage. Viper didn't have that limitation so I use there 1900.

The TEkin I used was a gen 1.