IMO it kinda depends on what youre intentions are for the eng.
If youre building a street eng that needs to be durable yet last many miles then I would personally use the softer bearings. This is due to their embedability of garbage that gets ran through a street engines oiling system and their tolerance to moderate detonation (they act as sorta a "spring" and absorb the hammering of detonation).
If youre doing a fairly "built" eng that will see high rpm and poss some short bursts of detonation that sometimes happens during the "tuning" of various parts then Id do the harder bearings myself. They will wear quicker in a street eng unless youre anal about oil changes but they wont be pounded out so easily by a short spike of severe detonation. They wont deform under high load (high boost/high RPM) which can cause the oil film to be interupted. This deformaty/film interuption would equal a scrapped crank and rod(s) at the very least. Ouch..
As for them being wider/narrower... Dunno bout that one. A crank only has so much room on the journal for a bearing and any wider would cause probs. A "narrow" bearing may exist but that only makes sense as far as profit per bearing for the manufacturer. Ive never noticed a diff in widths on a given bearing for a particular app myself..
Thats my .02 worth of thoughts.. Stick around though as Im running a sale later of buy one get one thought free.. Gotta have your coupons though. :grin:
