firstly, redline on the r33 rb25 is 6850 rpm, i have seen it with an ohm meter not a tach. the rb20 redline is lower than that (its like 6800 or 6700), more bs started by unstable (if you dont know who unstable is get the fuck out) and carried on by others to sell the cheaper swap to people who didnt know better.
-all the r32 motors and the r33 rb20/25(nissan put rb20s in r33s and r34s, they are used as fleet vehical) all have the same oil pump crank snout problem.
-the r32 rb26 has been known to have problems with crank walk, WHEN THE FACTORY SPEC BOTTOM END WAS PUSHED PAST 9K RPM IN GROUP A RACING. you will be hard pressed to find a well maintained r32 rb26 that has any of these issues, look at "the snails" old car.
-a smart person would use the rb26 oil pan by removing the driveshaft bits and getting the holes pluged. people pay $150+ finned aluminium oil pans for srs, you could make one for your rb less than the cost of a 25 oil pan.
-the r32/r33 rb20/25 motors have the exact same problems when it comes to the ring lands. both have weak pistons/rods and both have the same shit turbo.
-both motors were overrated from the factory, the rb25 actually makes around 230hp and the rb20 makes less than 200hp. the sr did make 202hp so yeah the rb20 actually makes less power than a redtop.
-it is easy to bring both motors up to factory specs by changing plugs and bumping the timing.
-the rb25 trans will hold more than 1000hp, the rb20 trans is a ka/sr trans with a diff bell. there are 600-700hp srs using the factory trans.
-rb30 block is like 1" taller than the 25/26 block. use a 26 top end or a greddy manifold on a 25 and you dont need to adjust the mounts. use the factory 25 plumbing and you need that extra inch. most people go to a solid mount thats 1" shorter than the factory rubber mount. since theres an 1.5" between the oil pan and the xmember in a 240 i think that would do it.

i cant speak for the dsm motor, its "greatness" probably has more to the awd system it was matched with, kinda like a gtr being great because of attessa. you get no arguement from me about the 2j. they are expensive though, a 2j with the 6spd trans will run you north of $5500. the rb25 neo has a gtr bottom end(non of the old problems) and a stronger trans. nad auto is selling neo front cuts for $3500 plus shipping, so which is cheaper? $2k will buy you a stupid big turbo and the injectors to go with it. personally i like my redtop and in the search for more power there is a reason im dumping the rb25 for a domestic v8.