where would be the best place to get the 1jz complete swap??

Location, price your willing to pay, and clip grade will all determine the "best" place for your situation. Lots of cheaper halfcuts from certain importers will be in questionable condition, other importers demand a premium for their reputation of bringing in quality grade parts. Even with a complete halfcut you will still need to buy a few parts, more or less depending on the year of your Supra.