I'd avoid the B205/B235 (or whatever it is) - the sludge is caused by the strainer on the oil pick-up tube being too fine. On the earlier engines particles which contribute to the formation of sludge would have been sucked up the pick-up tube, crunched by the oil pump and fed back into the engine. With the mesh being too fine to allow that to happen (presumably for longer service intervals or environmental concerns or some rubbish like that) the sludge forming particles stay in the sump and sludge builds up until that momentary point when the pick-up strainer is suddenly completely blocked and oil flow to the engine stops. The components are weaker as well, does not have the same rep for strength compared with the previous generation. Also has asthmatic camshafts for better fuel economy which you'd have to swap.
The reason the OEM management is preferable is down to the fact that your compensations and drivability maps are already fully configured. That takes weeks/months off your tuning time. You also get standard maps fully populated for normal running and usually for the majority of tuners a little tweaking of the boost request map is all that's required for a little bit of fun.
Ok thanks, the 2.3 sounds better too me being the larger capacity, bringing the torque down to a lower rpm is part of what I'm after. I've read quite a bit about the later ecotec engines having sludge issues and the pistons/rods being of a lighter design for efficiency, but lack the durability of the early heavy rods and pistons. I've read that the heads flow slightly better, but offset by the camshafts as you say being optimised for economy.
I guess the ecu side will be down to whatever I lay my hands on, being a complete ready to go installation or parts from down the back of someone's garage!
