Well, the thing that breaks engines, trannys, driveshafts, diffs and halfshafts is the torque. And especially on lowrpm. I will give you an example. It's believed that absolute limit of 1.9 tdi VP engine is around 160kw(~210hp) before throwing a rod. why? Because guys did small turbo upgrades, or enlarge compressor without enlarging exhaust, so turbo stuffs more air in, but it exits through same small hole so it's choked even faster. They make stock Max torque of like 250nm at1900rpm and 66kw. And 350nm was hard step to overcome without for a lot of guys without clutch. Būt then some dude decided to weldon a turbo from 3.0d and it spools late making full boost at 2500 Max torque at 3000 and it's like 550nm(stock clutch holds 400 with smooth torque and boost ramp) and close to 300horse spining to 5500. And i think some guys deal with clutch slip with smoothing and delaying fuel and spool ramp to later rpms. this beamer makes above 0psi only after 4k, at full boost at 5.5k so it's no problem that it's torque is high. OOHHHH and Also whats great about a lazy manufacturer who uses same sizing for everything is that4cyl engines and 6cyl engines and gearboxes boltup to each other. Older 5speed diesel gearboxes too. It's fairly simple swap to put 2.0-2.3-2.5-2.8-3.0 and leaving it stock has no problem for 4cyl gearbox. even clutch disk splines are the same. Same way you can put stronger 6cyl box on 4cyl engine. Būt 4cyls have Tiny cluth disks. 215mm or 228mm. 6cyls have 240mm and that's not a problem too, because all flywheels use same bolting up 8bolt pattern. He needs around 700nm which is no problem to hold 800 with sintered disc and diesel pressure plate from e60 530d.
