If you want AWD and RWD, buy MA-010. If you want FWD buy MA-010. If you want more wheelbase lengths, buy MR-xx. If you don't have that much $ to tank into upgrades/replacement parts, buy MR-xx.
MA is a superb chassis, but you won't shink it to 86mm or extend more than 98mm. You'll NEVER break 180 gram ready-to-run weight either, with stock chassis.
Just given the fact that 2.4 MA's are harder to come by, I'd recommend getting it first and then see if you even need an MR. Only reason I got MR and MA is because I started with MR and wanted to keep a familiar platform when I was upgrading to 2.4ghz. Otherwise I'd be better off with 2x MAs.
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