Air Power Systems in Bayswater are apparently OK. They've done MX6's before (probably Telstars too). These are the guys who do Unichips as well so if you're lucky (or unloucky as the case may be) they'll sell you a unichip!
There are really HEAPS of chassis dyno shops around tho. Go somewhere local so you can build up a bit of a relationship, maybe.
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