The difference between short and long tube headers is very moot point. The only reason why long tubes are considered more effective is because the exhaust pulses are less likely to interfere with each other at the collector which will slightly improve scavenging. The length really does not matter that much on a VG engine because of its 1-2-3-4-5-6 firing order. Both short and long tubes are effective in increasing mid range torque and high rpm horsepower. If you want more low end and less attention from the cops, stick with the stock exhaust.