[BoxerFanatic]

See, now this discussion re-affirms my wish for a dual-mode exhaust system.

Full equal length primary tube headers into collectors and low-restriction catalyzers (one for each bank)

Then into true-dual 2 or 2.25 inch pipe runs to either individual resonators, or a common 2-in, 2-out resonator box, pretty much parallel straight through, or maybe internal cross-over. (I've been looking at Stebro's Ferrari exhaust products... very nice... they run several 2-in-2-out muffler/resonator boxes, sometimes even 6 of them. More resonator length than pipe length in the exhaust system.)

Two pipes around the rear differential... hopefully two smaller diameter pipes will preserve a bit more ground clearance, as well... with each pipe diverging toward the outboard exhaust tip positions.

Where the current huge muffler is... I would use two mufflers, each same-side input and output, similar to a C6 corvette, or modern Porsche, or some sort of lateral criss-cross layout, if I have to use linear flow mufflers.

But the dual mode would be butterfly valves in Y-pipe junctions on each side. Closed would divert the exhaust through the muffler system, and back out to the exhaust tip.

Open, however, would dump straight to the exhaust tip, with the least amount of bending or impedance as possible.

The tips would be larger ovals than current, and set up with a merge of the inputs from the mufflers, or the direct valve on the same side of the car.

The valves would be electronically actuated, with a three position switch. Manual Open, Automatic, or Quiet (always closed)

Automatic would trigger the exhaust to open with the IRIS intake valve opening, above 4000 RPM. Possibly also triggered along with POWER mode even below 4000RPM with sharp throttle input.

Of course, all of that behind a nicely built high-compression NA EG33 engine with cams and other upgrades, and a STI/Spec.B 6-speed manual gearbox. A ~300 NA flat 6 horsepower that sings a sweet song.