How much do I damage my engine when driving top speed regulary?

I would gladly trade up my a4 tdi for a 520d
Comfy and fast commuting, probably even more fuel efficient, too

Your bearings will be hammered and possibly flake or crack apart and then you'll be in trouble. If the rods don't split and you don't drop a valve, you can expect the piston rings to start blowing by much earlier

Top speed would likely be higher with bigger wheels. Linear speed is the product of angular speed by radius, in pure rolling conditions (wheels aren't sliding).

>I usually drive slow for about 15 and then floor it for about 30 minutes while reving it at 5500-6000rpm
lol at regularly just casually driving around at terminal velocity.

Nope, I wouldn´t put any more power to the ground with a higher tire diameter.
That would have the same effect as my 5th gear.

>Be Miata owner
>4100RPM @ 80MPH
>Do this for hours on end
>Engine still running at 249k miles

I don't even run nice oil or anything, just SuperShit walmart 5w30 and a FRAM filter. Only had the car for 35k miles though.