the A4 generations...

can anyone telll me the different generations of the A4, the years of each gen, the engine and horsepower. thanks. im supposed to be getting a car for graduation(highschool) and i like the firebird V8(98-01) but cant seem to find one in my area, and if i do its alot of $, the A4's seem to be less priced around those years and i read here that the 1.8 mod easily with chips and stuff. thanks