Pennsylvania cops cannot pop your hood and check for modifications, this isn’t gay cali where they have ref’s and shit, thank god.
If it’s obd2, the greddy kit will probably still pass as long as you have no engine light because it uses the piggy back system.
if it’s obd1 and you don’t keep it exempt, good luck passing the tailpipe test.
best way to do it is keep it under 5,000 miles a year, make good with someone that does inspections/emissions, or do some shady shit with the odometer.