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the market for a 13 year old GTI with only 9k on the clock is slim. the car commands a premium price.
If its priced right for the market, you should find a buyer.
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so providing him with some numbers may be my last chance.
Doubtful... If he can't get a straight honest answer about the car being legal (needs new tank, injectors, header, etc), then how is he going to get the correct acceptible limits from those same technicians?
The exhaust gas limits should be the same for any state (Colorado, California, etc)... The car is considered a "Federal" or "49-state" car, and has smog standards for such.... Those standards should not change from state to state.
In California, Federal cars are legal as long as they meet the FEDERAL requirements (and are not considered 'new'). They do NOT have to meet the "California" specs nor should they be required to be retrofitted with anything (as long as all federally-required smog equipment is present and functional).
I'd say it obvious that he doesn't really want the car.