Why would you pay $200 to put the stock exhaust back on? It's a couple bolts and a few hangers. The hard part is cutting the stock exhaust in the first place to install the PE.
Ultimately, a stock exhaust is worth little more than scrap value at best. It's not like they rot out, what little demand there is is due to accidents. The way to maximize revenue is to sell the car with the stock exhaust, then sell the used PE.
'11 328! Touring - Tasman on Chestnut, 6spd manual, factory upside-down "i" option
'16 M235i - Estoril on Oyster, 6spd manual, sunroof delete, Euro Delivery on 8/21!