Zoomies and an exhaust tunnel

I will soon be installing a new exhaust system. There is a chance this will entail stripping off lots of the undercoating under and in the car (I undercoated the inside when I had the car stripped) and doing some cutting

With the new exhaust with the long collector I may need to modify under the car to make it fit. This mean cutting the floor and making an exhaust tunnel then adding metal to the top to cover it. The floor will look like yard does when a mole goes through it.

Because I am basically lazy I was thinking I would be doing less tedious undercoating removing if I ran the exhaust out the side by the passenger rear wheel Hence the zoomie idea.

Since I am making a tunnel I might as well make one big enough to stuff a muffler along with heat shielding. I could leave the shielding out and claim to have a heated passenger seat like the Audi Quattro's. Regardless the undercoating must go.

If zoomies are a bad idea I am very open to what would be the best exhaust system for my car. What do they use in the FP and GT4 classes? Does anyone have any pictures of race exhaust systems?

Thanks,
Calvin