I've read on a lot of different posts here that the gap between 3rd-4th and 4th-5th is pretty bad, also have not found a suitable replacement for the tranny without serious modification to the truck. I am putting a turbo and was wondering if that will take up some of the lag in the shift points? Obviously won't change the shift points in the tranny just was wondering if anyone who has put a turbo on the M800 trucks have noticed a difference when it comes to shifting? Don't really want to switch to an automatic but if the gap is still present with standard 5 speed and can't find a suitable manual replacement without changing over clutch pedal, bell housing etc then that might be my only way to go.... simply because I know the allison mt654 will work. Any input or ideas always welcome. Thanks.