From what I heard, the rear drive style engines are different than the front drive engines and it's the front drivers that had the head cracking problems.The cracked heads leaked coolant into the oil ,gumming up the lubrication system and ruining the bearings.The thrown rods were generally in the Fiero models, they could generate enough cornering G's to starve the oil pick up,a rod bearing spins from lack of lube,the rod welds to the crank,breaks, goes through the block folloewd by a few quarts of oil which catches fire on contact with the hot exhaust.
So it seems the S10 style 2.5 is the better of the bunch, but won't fit in a front drive model situation.
