Thanks! I'm what about EGTs? Do you feel that there wouldn't be a measurable difference between a 3.5 and 4".
"A different exhaust system is also needed to make the conversion, and it is available from Banks. The new system bolts on via the original hangers, so no welding or modifications are necessary. A custom, 14-gauge crossover pipe bolts to the inlet on the turbocharger manifold and to the stock exhaust manifold on the driver's side. The forward section of the replacement single-exhaust system is mandrel-bent 14-gauge steel, aluminized for rust protection; the rear portion is 16-gauge tubing. The standard Banks pipes and mufflers, as tested, have a 3-inch diameter, which has the ability to flow a lot more gases than the stock 2 1/2-inch system.
An optional "monster" exhaust with 3 1/2-inch diameter tubing is also available. Banks told us that the larger-diameter system, which we did not test, is good for about 4 or 5 extra horsepower at peak rpm."
- Banks Sidewinder Turbo Trailer Life - March 1993