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...
Here's some pics of our last Sat wedding convoy down to Melaka to attend one of our members wedding. It was really a hot day in Melaka and only a few members managed to join due to work and busy schedule.