goals. QUIET FOR STREET. High flowing for 250 shot pf nitrous ontop of 500hp 468

I have a 68 with 468cu e heads(round port), extreme energy 274 comp cam, dougs headders 3.5 collectors. I did a dsc mini tub kit in the rear with 315/35/17 goodyear eagle f1-d3 tires. the front of the rear springs are in the stock perches, but the rear springs have been moved inward 2 inches on each side, as the shock towers have been moved in as well. The fuel tank is narrowed 2 1/4 inches on each side.

I want really quiet exhaust on the street as I live in a subdivision, however I want it loud too at the track, and quite frankly.. when I want to show off or piss on a ricer at the light.. .hehe

the motor should have around 510 Hp, with 600 tq at the crank, plus 2 x 125 shots of nitrus.. so i'll be pushin 750 hp.

my idea is for cutouts at the collector, a crossover.. then 3 inche primary tubes to 3 inch vt mufflers with 2.5 inch tail pipes.. taking in account that exhaust gasses cool and 3 inch isn't needed that far out and the problem that no one wants to bend 3 inch pipe in raleigh and its going to be tight.

its my belief that I won't need more then 2.5 inch flow after the muffler.. unless I hit the nitrous which i'll have the exhaust cutouts to take care of the extra flow over 500HP.

the car is lowered to the ground 2 inches..maybe more.. its pretty low. I really need the muffler cases to fit there holes.. is there a vt muffer that will 'fit the bill' ? thanks for all your help.. stock length muffler is what.. 14 inches?