Why do you think the milage is gonna "suck"? It will only "suck" when you are making the boost. You wont be on boost unless you want to and that will require you to be getting in to the throttle.. When you are driving like a citizen you wont be on boost, not making gazillion horsepower, not draining your tank by gallons per minute, not experiancing hardly anything different than you did with the stock version. Thus no different milage--in fact there have been a few situations where milage can improve during the non-boosted driving experiance due to the better atomization of the air-fuel being "whipped up" by the turbo's compressor--now at the same time dont count on it--I said "sometimes".
It takes a certain amount to propel a vehicle down the road at any different speed. Different vehicles-different hp requirements. An Old 1600 MGA might require say, sixty hp to go down the road at 60 mph. And at the same speed an MGB will require more hp due to its larger frontal area (which is why they had to put bigger 1800 engines in the B--kinda embarassing to the factory to have the older car be able to go faster).
Your throttle is your horsepower maker, the drain valve to your gas tank, and your turbo is the pump, so if you dont need the extra horsepower at the time, dont activate your horsepower maker, or your gas drain valve or your pump and you wont be using anymore gaoline that a stocker. But all that magic horsepower is very addictive, so spend the money for the safeguards, the forged pistons, the intercoolers, the water/alky injectors and magic timing adjusters--'cause they will always be there thinking "careful" when you aint. Oh yeah, dont worry 'bout the 409 stainless, the vendor will love to sell you the 300 series for your exhaust pipe!

Last edited by preacher-no choir; 09/20/13 03:02 PM. Reason: spelling