It's a great buggy for a beginner racer. It's easy to drive and very durable. If you really want to get into racing, a kit is a good idea. I went the RTR route, and after a while, I wish I would have gone with a kit.
The first things to change out would be the servos. the radio gear (MX3) is actually a very good radio. Hop ups to get are the CNC front knuckles, and CNC servo saver if the stock one breaks.
The buggy is competitive out of the box, but some better electronics and CNC front knuckles, it will be a very good buggy. Make sure that you clean the diffs and replace the grease with silicone oils for tuning. Eventually you can work on setup with different oils and suspension positions.
Good luck