MAP = manifold absolute pressure
The absolute part is because it is not reading differential or 'gauge' pressure but reading the actual or 'absolute' pressure. This is important for mixture determination. Thus, at sea level, with the engine off, it reads about 14.7 psi or 100 KPa, whereas a differential gauge would read zero (regardless of altitude).
Read Corky's book, good start.
I am happy with my BEGI-s kit. It is a good trouble free starting point. When you are ready to get one let me know as I have some components I am selling from mine (shameless plug)
Torsens rock, I love mine. Excellent, **** quality rear end behavior IMO. My car came with one. For some reason they seem to be bad for drag racing based on some of what I have read here.
Read, read, read, search, read, search, read, read, think, search, read, read, think some more, then post.
Welcome, from a fellow Texan.