I would still recommend trying out the RX8. There's not much worry abt the 120days warranty. If it's a known issue that other guys are experiencing. Tekin will still repair/replace yr unit even pass the 120 days.
Alternatively, you might try the Hobbywing Xerun. Between my Truggies & Buggies, I have used the RX8 & Xerun. My opinion is to give Tekin a try since you're in the U.S