You installing with stock twins or a single/upgraded twins? USDM or JDM harness? Motor from an Aristo or a Supra? R154 or auto?
If the motor is a rear sump, you are going to want to use JZA70 brackets or BIC brackets to bolt it in, if you are using a JDM harness, look into the alternate wire routing method (hole in firewall) and IIRC, all you need to do is wire it up to the fusebox and wire the dash harness. (This is all assuming that the motor is already bolted to their transmission of choice). If you want to take the super easy method then pay Dr. Tweak (search his username here) to do your wiring harness for you (tell him foreverpsycotic from SupraMania sent you). IIRC he charges around 500 to do the full harness conversion including return shipping and he takes about 1 week to do it.