just for me, i prefer mugen MTX-3 , i don't know why,
i already use g4 for about 3 months, the result it quite good, but i must have some option to run it better that the original, like 4mm chassis, n alum steering rack.
but , if you want to buy g4 EVO or MTX-3 Prospec, you better buy the MTX-3 one, maybe the price more expensive than EVO, but you get more option from the MTX-3 and it more confortable for me.hehehehehhe.
that just my opinion
that depend on you