Actually I like vacuum condition like this.... no mtx5 yet.

I don't want to buy mtx4, mtx5, mtx6 too quickly. [ If you collect tamiya cars.... you'll know what I mean ]

more over, my mtx4 is still capable car without 2nd gear broken syndrome ( my tips : use plenty 3x12mm titanium screws all around to stiffen up chassis rigidity especially on the rear bulkheads area ).