When it comes to drums, the general rule is "NEVER let someone else play your drums!" because you just KNOW the guy is gonna beat the crap out of your instruments with complete disregard for somebody else's hard-earned possessions and correct drum-playing technique. But what's the case when it comes to RC cars?
I'm guessing the majority of us are far from elite-class RC drivers; those who are, are making a name racing their cars, not writing on forums.
I would be intrigued to let a person with real racing skills test-drive one of my builds around the track to see how well they perform...because my driving skills would hardly be up-to-the-task. You could give me the top-of-the-line, modded-to-the-nuts cutting edge race car and I'd probably crash it so often, it would make Windows Millenium look good.
But under the control of a good driver, who knows?How many of you guys would trust a known 'good' racer to test-drive your custom RC builds to evaluate & tweak performance?
They always prove that my car is capable of turning much faster laps than what I'm turning. 
). Incredibly fast, but unique driving style and setups mean they can be hard to get information about setup that transfers to you and your cars. Not to say they are tight lipped about setup (some are a-holes though), but how adjustments effect their cars is different than yours because of driving style differences. Matt was always extremelly helpful, and never balked when asked to drive my cars or offer setup advice. 
