Luckily I do not have the rust issues here. Took about 1 hour to remove the manifolds and put Thorley tri-ys on the 87 G20. Took 20 minutes to remove the old exhaust with a sawzall, then took about 3 hours to build the exhaust to the rear axle. About 1 hour at the exhaust shop a day or two later to get the tail pipes fabricated over the axle. It took me the most time laying out the exhaust system how I wanted it, measuring everything 2-3x then cutting stuff to length. If it had been an actual pre-fabricated setup rather than a u-build it kit would have been much quicker in that regard.
The nice part about removing an old exhaust system that you are not planning to re-use any of is that it can quickly be removed by a metal blade in a reciprocating saw aka Sawzall.
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