Terry Houston vs. ATR downpipe

[1987BuickGrandN]

Whats the going rate for a nice terry houston style downpipe?? differences between the terry houston and the ATR pipe??

 

[GrandNational87]

a houston 3'' dp with an integral wastegate with cutout or catalytic converter and hardware for for (years 86-87) 439.00 dont know about the atr...