When I started racing, I went the cheap route buying a used RTR touring car. The car wasn't good but neither was I, so it was fine until I became a better driver. At the time I didn't want to invest in something like an Xray because it was expensive toy for me I was only using ~10 a year.

Some of the 3racing kits look very good. I've never personally raced one, but I know several guys that have. As 0010 said, the durability can sometimes be less out of the box. So research the specific kit to see if there's a weak part/design and upgrade or aftermarket parts to fix.

Also nothing usually wrong with buying a used kit from a name brand. I'd strongly suggest you tear the whole thing down and rebuild it to make sure everything is correct.