Kit could be better but it all depends on what you're planning.

For example, if you're going big dollar brushless you're probably still going to need HD bevel gears and better rear lower links like VP so the extra good bits in the kit might be replaced anyway.

The RTR is surprisingly robust for a brushed setup and you could pick one up lightly used for a bargain. I'm running stock gearing on 3S with a Titan 550 size 21T (~28T 540 size equiv I guess) and a Hobbywing WP 80 ESC both of which are extremely affordable. It's a fantastic setup for rock bouncing and the Bomber totally stock has handled many months or bashing around. I simply added a $5 metal servo horn. Not a single thing has broken apart from tha stock plastic horn). Loads of fun and temps are great in the cool weather. A 2sp will give you great low speed crawling in summer. That's my plan as brushed worked great contrary to pop op and is very water tolerant and they are dirt cheap to replace.

Add a Tekin Pro or Roc412 and you will start spending up big on trying to hold everything together.