I don't understand why people "think a 383 costs more than a 355" especially if we're talking all forged rotating assemblies, because both cost exactly the same. You may or may not have additional machining costs depending on the crank and rods you buy. For me it was a no brainer I went with the cubes 383 all the way and as for the rear, with an m6 car S60 is the route I went. I've broken 3 - 10 bolts with m6, drag radials and good track prep, never ever again. Shoot if a guy can spend $2500 for cnc ported heads then why not for a stout rear that they shouldn't have to ever change.