puttin on a turbo not only increases your power and fuel mileage but it does make your motor work less. i have 2 6.9s i have a 86 ext 2 wheel drive i have an aftermarket ats turbo its a 4 speed with a gear vendor over drive i got alot of money wrapped in it. i got some other work done to it like ip turned up and injector work. i also have another 86 ext cab 2 wheel drive but its an automatic and i dont have a turbo on it my turbo truck gets better fuel mileage egt runs 80 degrees cooler on it as well. guy i bought it from kept records of everything when i bought it it had 350,000 on it i put a turbo on it 6 weeks later turned up my ip and bought different injectors for it and i aint dont nothin else to that truck motor wise at all. and i can hook up my goosneck stock trailer load it with 30 sows and out pull my buddies 01 cummins all day long and get better fuel mileage doin it.