Off-the-shelf stainless exhaust systems?

[StoningtonQB]

Hey guys. Been looking to replace my exhaust that the PO installed (LMC Truck cheap-o) with a quality system. I've only seen 3 exhaust systems for our trucks:

Magnaflow 16643 - $678.97
Flowmaster 817654 - $653.97
Pypes Performance SGT79S - $459.97

I'm leaning towards the Pypes system because of price (and uses X-pipe), but catalog claims it's for "67-82" pickups. No reviews I've seen are from 67-72 owners. Who has experiences with any of these exhausts? I expect a bolt-on experience but don't mind if the downpipes need some modification.