I can recommend the Kyosho Lazer ZX-5. Had one last year and used a LRP Sphere Comp + 4 star with Orion Platinum 4800. Incredible performance and control. At $299 the ZX-5 is a very good choice. You can upgrade it later if you want a style similar to the BJ4 and TRF501X. I think the conversion is made by KMC. I like the original "tub" chassis and I wouldn't recommend converting it.

My opinion is that a 4wd is easier to drive if you're using a fast brushless or brushed motor. I haven't used lower than 13 turn in a 2wd.