In terms of running aftermarket systems, it doesn't look too good if you're a Virginia resident.
This part is no problem: You have to run a muffler, not a straight pipe.
[From the Virginia state legal code]
t 46.2-1047. Muffler cutout, etc., illegal.
It shall be unlawful to sell or offer for sale any (i) muffler without interior baffle plates or other effective muffling device or (ii) gutted muffler, muffler cutout, or straight exhaust. It shall be unlawful for any person to operate on the highways in the Commonwealth a motor vehicle equipped with a gutted muffler, muffler cutout, or straight exhaust.
(Code 1950, t 46-306; 1950, p. 54; 1958, c. 541, t 46.1-302; 1964, c. 628; 1989, c. 727.)
But this one is more strict:
t 46.2-1049. Exhaust system in good working order.
No person shall drive and no owner of a motor vehicle shall permit or allow the operation of any vehicle on a highway unless it is equipped with an exhaust system of a type installed as standard factory equipment, or comparable to that designed for use on the particular vehicle as standard factory equipment, in good working order and in constant operation to prevent excessive or unusual noise. An exhaust system shall not be deemed to prevent excessive or unusual noise if it permits the escape of noise in excess of that permitted by the standard factory equipment exhaust system of private passenger motor vehicles or trucks of standard make.
The term "exhaust system," as used in this section, means all the parts of a motor vehicle through which the exhaust passes after leaving the engine block.
Chambered pipes are not an effective muffling device to prevent excessive or unusual noise.
(Code 1950, t 46-305; 1952, c. 455; 1956, c. 651; 1958, c. 541, t 46.1-301; 1960, c. 120; 1970, c. 266; 1972, c. 66; 1989, c. 727.)
This would seem to suggest that ANY aftermarket system that is at all louder than stock is illegal. The bold sentence (emphasis added) is the killer. But we wonder how exactly you PROVE that the system is louder than a stock one. Side by side comparisons? Seems impractical, especially on the side of the road. Other than this technical detail, it looks like the intent of the law is to make any louder-than-stock exhaust system illegal in the state of Virginia.