I have the hyper 7 pcr rtr. Like King said if money is an issue go for the hyper. You will spend alot of time reworking the diffs and shocks and suspension. Not to mention getting rid of the stock radio system.
Alot of guys at our club have mugens and once you get the hyper set up it is just as fast as anything out there.
That being said, I now have a new starter box and engine and would have been better off with a mugen to begin with. Performance wise, with a little work the hyper is a capable buggy.
On a side note, my friend is selling his mbx5 so he can get the prospec mbx5.
This thing is less than 2 months old and has alloy hinge pin mounts and various other mods. He is looking for $400 for it. Trust me this is a good deal, this thing is race ready!