Do you guys even know what an FMU does? Increases fuel pressure according to the intake manifold pressure. More boost = more fuel. It can be tuned safely, I'm running one on my sr20det right now.
As for the stock exhaust, three of my turbocharged friends are currently running stock exhausts on their sr20det's, with no problems. I ran a stock exhaust for 8 months. I have it on my car now to pass inspection...and I guarantee I'd pull away from any of you (except 20psi240sx and Wagz) on the highway the way my car currently sits -- FMU & stock exhaust.
Next time, don't be so quick to criticize other people's tuning decisions if you have not had the first hand experience yourself. Theory and general rules of thumb do not always apply.