a properly tuned length extractor does not compress the exhuast gas from 4 pipes into 1 pipe... the length of primary and secondary pipes are tuned so that the exhaust gas pulse can travel one by one into the pipes according to ur engine firing order...
Very good buy, 2nd car with very low mileage (12,000 km) like brand new with Nismo exhaust. Only serious buyer welcome. Contact Francis Ng 012. 229 5609