Hi and welcome to the club, you will not regret it because there is so much information and really a lot of members who know a lot about Supra's.
dont just jump in and do a lot of alterations to the car, give it a while, go through all the forums there's just so much info on the car.
A few things I will say is, be carefull (sounding just like your Mom), its very easy to crash one of these if your not used to it and with referance to your BPU you may either have a boost controller or a restrictor ring fitted in your exhaust. If its a boost "con" then there should be a box usually in the cab but sometimes in the engine bay, (about 2 or 3 inch sq by about 1 deep with some sort of readout).
With a boost controller you can alter your boost pretty easy but its not advised to go more than 1.2 bar, if its a restrictor ring then you can get a larger one to take you to 1.2.
All the best.
Bob.