exhaust next

i need to buy an ex system for this 73 duster..cant seem to find anything from sum or jegs that isnt from collectors back..im running stock manifolds and need to buy from stock man back or buy the collector set and buy downpipes...any one have any advice and part numbers to do this with..one manuf has a complete set but it is a lot more than i would like to pay...any help would be appreciated..j