Top down driving hides a lot of imperfections, read noise masking, in the powertrain.
I'll always remember in the 70's in some muscle cars the tranny made as much noise as the engine and then taking your foot off the gaz would cause the tranny to make even more noise and WHINE.
Unfortunately, type I trannies are older technology and the best rebuilding guys sometimes get all the stars aligned and the tranny is quiet, maybe quieter than most.
Some are quite noisy, whiny, etc. Add the changes to fortify the box and gears and your at a new level of cruder tech as Carey said.
I think on any new build especially a coupe, a rigorous amount of sound insulation, think double should be done. Otherwise, you will be in a drum of reverberation.
Just saying.