I have never heard of a "low end failure" on an L67. The only problem I really hear about these engines are from people running insane amounts of boost or having a bunch of knock, that chunk pistons. But in stock form, a properly maintained L67 will last over 200,000 miles. Sometimes the bearings on the supercharger go bad, but again, a properly maintained */C will out last the engine.
The GM 3.8 is an engine that has been engineered and improved upon for decades. They just don't 'break,' unless you really don't take care of it.
The only weakness is in the transmissions ... only if you modify the engine though.