Another big consideration is you have to have a CFC card to purchase refrigerents by law, I am a HVAC Serv. tech and the EPA has handed out some heafty fines. Best to buy preassemble, I have done refrigeration work for over 15yrs. and I can honestally say that I would buy instead of build unless building it was part of the fun, of corse it would just be a job to me , YUCK.