Low on ammo, make sure to use the skill tree to fix that. Sadly lacks JJs, but you'd have to remove the MG arms.
Well, IMHO 143 km/h is fast enough most of the times, unless you need to chase a locust... If that is the case, I think it would be the best NOT to engage him alone with non-Artemis SRMs and machineguns because you are gonna miss and spread the damage a lot. IMHO build like the huginn are most effective versus 35 tonners or heavier. Anything smaller will probably be too fast and to small to be hit properly by SRMs and MGs.