The VW and BMW lifters were both made by INA, save your time.
The VW/M52 lifters are 49 grams, so x16 that's 80 grams or 2.82 ounces or .176 pounds more than the S50's. I'll stick with the drop in lifters and not bother with trying to source M3 cam trays that have to be modified to fit. Good info all around tho

There has been some talk about using 49 g hydraulic lifters from some VW models to lighten the valvetrain.
I happened to notice from internet ETK that BMW also uses 49 g lifters on M52 engines!
I did bit of calculations (found useful equation from a book I have) and valvetrain (lifter, spring, spring plate, valve, collet) would be about 10% lighter with 49 g lifter compared to standard 67 gr lifter. That means that everything else staying as it is, engine rev limiter could be safely raised from 6800 to 7200 rpm.
M52 engine does have other interesting parts too... Spring plate is 2 g lighter (8 vs 10) and spring itself is whopping 13 g lighter (38 vs 51).
If those parts would be used on M42, valvetrain mass would be 18,8% lighter which means safe rpm goes from 6800 to 7550. That is of course in case that lighter M52 spring has same spring rate as standard M42 spring. I somehow doubt this as I suspect that BMW just optimized valve train power loss by using softer springs (hence their lower weight) made possible by lower lifter and valve plate masses.
Anyone know actual spring rates of standard BMW springs? Or Dbilas or Shrick springs? Lighter M52 lifter and 20% stiffer springs would guarantee happy revving all the way up to 8000 rpm 
And your math is off a bit Ralph. You didn't separate the different weights of the in/ex valves so really it's:
M42/S50 = 2,172g = 4.788lbs
M42 Light/VW = 2,252g = 4.964lbs
M42 Light = 2,660g = 5.864lbs
M42 Stock = 3,470g = 7.650lbs
Best answer, get an M42 head from 9/1992 or later and add VW/M52 lifters.
http://www.realoem.com/bmw/showparts.do?model=BE53&mospid=47480&btnr=11_1143&hg=11&fg=25I question whether the VW lifter is up to task as much as the BMW unit. Only a side by side comparison can show the difference.


