Congrats to the OP on his new manual trans E53!
Have had our 2001 since new, ~ 145,000 miles now, (3 cars so it is not/has never been a DD). Still runs like a top, and is the 2nd best car I have owned in 62+ years of lots of cars.
Orig clutch, et al.
Tips: 2nd gear starts are often easy, esp on flat or downhill grades.
1st is a stump puller, short shift to 2nd or 3rd frequently, for me.
I have had the trans fluid R&R a few times over the years: Redline, forget the weight.
Have Style 132 staggered 19" wheels on it for past 19 years, in place of the orig Style 69 18" sport package wheels.
Have opened the moon roof maybe a half dozen times; don't care about it but the point is the less a moon or panorama roof is opend/closed the less likely it is to every leak, imo.
Long day trips, NC Mtns to NJ to see our adult kids a couple three times a year: easy 20-21 mpg by the arithmetic tank to tank. Often ran 89 or whatever on those tank emptying trips. Car didn't care at highway cruise speeds, imo.
Oil/filter regularly when newer, now just once a year whether is needs it or not. Switched to M1 0W-40 years ago: cold morning starts at our nearly mile high Mtn home altitude and I like the 40 weight aspect for those long fully warm/hot engine day trips. Just my opin.
Yes, cruise RPMs are high; has not seemed to have a deterimental effect on the 3.0 IL 6 over 23 yrs and those nearly 150,000 miles.
Recall a poster or two back in the old days of this board's previous iterations doing 6 Spd R & R vs our 5 speed trans...
Have fun, enjoy the car and that 5 Spd is a bit of a 'car safe/can't steal it' in today's world, imo.
GL, Ol'UncleMotor