Replacing stock single exhaust with dual

[NH455]

Any tips on replacing stock single with a dual exhaust?...recommended suppliers? I came across a 304 stainless on eBay for about $600 that is advertised to fit a 66-70- Toronado, but wondered if that is a sure fit for my car. BTW, I'm mechanically inclined, but not a mechanic.

If I did this correclty, this is the link:

http://www.ebay.com/itm/1966-70-OLDSMOBILE-TORONADO-DUAL-EXHAUST-SYSTEM-304-STAINLESS-W-OUT-RESONATORS-/200830795168?_trksid=p5197.m1992&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D14%26meid%3D2693355203929543277%26pid%3D100015%26prg%3D1006%26rk%3D1%26sd%3D200830795168%26

[69W34]

'Stay away' for this guy .... I am aware of two members (there may be more) that have purchased his system and in both cases they found the construction of the muffler internally was botched, leading to over heating and poor performance. Also the tail extensions of the resonators are squared off short, thus do not extend all the through with tapper to match the chrome tip.