Originally Posted by lejeunebimmer
I will give this as best a shot as I can.
-M54B30 has an Alu-sil block with the crank and bearings out of an S52 (I don't know if it's the B30 or B32 kind).
-S54B32 has a grey cast-iron block, with a much improved design of the crank and rotational assembly out of the S52.
-M54B30 has 10.2:1 compression
-S54B32 has 11.5:1 compression (here is a big part of the power!!!)
-M54B30 has hydraulic lifters (will most likely collapse in on its self @ ~7500rpm)
-S54B32 has solid rockers (partially enabling the 8k redline)
-S54B32 has more aggressive cams (more power)
-S54B32 has ITB (more power)
-S54B32 is more aggressivley tuned (more power)
-S54B32 has more freely flowing intakes and exhausts (more power)
Take an M54B30 bore it to .30" over, throw in some forged connecting rods, and 12:1 compression pistons from Sunbelt, shave port&polish the head, install 1mm oversized valves, heavy duty valve springs, schrick cams, use the intake manifold from a WTCC (do they even have these that could fit?), bore out the throttlebody, throw on a quality set of stepped headers, to a free flowing 2.5" or 2.75" exhaust, maybe use an intake like the dinan CAI (either one), eliminate the A/C, underdrive the waterpump (race one now), underdrive the powersteering, underdrive the alternator, custom tuned or even designed Engine Management software, light weight (like 8.5lbs) flywheel, drysump oiling system, improved vibration dampner (crank pulley), so that you can actually safely rev to like 7500k (maybe remember you still have hyraulic lifters...).
You will have sunk 25k+ into it to make a racing engine that MIGHT make 350hp if you're lucky.... So you see, you could make the power applying the same measeures to the M54B30, but it would most likely have to be taken to extremes, and be overly pricey....