1968 Porsche 912 Question?
 

my customers have a 1968 912 porsche it has koni performance indepent suspention
it has a 930 porsche spoiler the motor was jsut rebuilt by a porsche shop it has some of the best parts it can in it and it has dellorto dual carbs a 89 prosce front bumper it was jsut resoterd and MB SD C4 is painted origanal color new interior new tiers it was given to my customers by my customers grandfater my customers was wondering what it is worth and how could my customers give it more power and what exhaust is best