Generally, low and slow cooking is reserved for tough cuts of meat that have a lot of colligan and fat. Lean cuts of meat need to be cooked at higher heat to avoid drying out. Loin is a lean cut of meat.
I have had excellent results cooking pork loins by rubbing with favorite herbs and spices, then cooking direct heat, 350 dome temp, and pull the meat when the meat temp hits 135 internal. Turn the loin a number of times during the cook to get a nice crust. Allow to rest, wrapped in foil for 1/2 hour after cooking to redistribute the juice and let the meat temp coast up to 140. Loin can dry out and get tough if allowed to cook to well done. It normally takes around 1.5 hours to reach target temps if you follow this advice. The main thing you need to do is do not overcook the pork.
I would give this a minimum of 90% scam. Anytime there is free shipping on a heavy/bulky item and really low price is a real good indicator of a scam. I have been privy to numerous ones involving farm tractors that were very thought out. If the seller has low feedback numbers beware. Find the sellers name and address and do a little Google searching. This DEAL smells to high heaven to me. If you ever tell yourself, "this is almost too good to be true" your right...it is too good to be true.