Just bought a 1991 931a2 it is AWESOME. however on the journey home it only reached a top speed of about 53 mph. it has 14 r20 super singles, i have read owners going 60 plus. The truck was overhauled in 09 and has 1000 miles since and has MWO tag of 8/12 i will change all filters soon and i am running complentary diesel from the gov. about 90 gals. im hoping new fuel and filters will help. Next the accelorator, i dont have another five ton to compare. you have to mash the pedal HARD to go anywhere highway driving for more than a few minutes requires 2 feet on go pedal to maintain speed is this normal. on a side note i brought the truck home for my daughters 4 birthday and gave some rides to the kids what a blast.