VA cops can ticket you for tint. However, look into the Driver's License Compact of 1965. While you have to obey all driving laws of the state that you are in, the Driver's License Compact states that every state signed onto it (VA and MI both are signers on the compact) has to agree with the other state's driving laws.

You should have just told the cop that your tint complies with Michigan Inspection Laws. I drive in VA alot and have had Fairfax County cops twice tell me about my exhaust system. I tell them that I have had a Maryland State Police officer tell me my exhaust meets all Maryland Inspection Laws for exhaust systems (which he did tell me), and they leave me be and tell me to have a nice day.