When i was new to the site many of the abbreviations looked like gibberish to me. So heres a list of commonly used abbreviations and what they stand for. If this becomes popular i will also add descriptions, alphabetize it and what not.
S/C = Supercharged
N/A = Naturally aspirated
Cai = Cold air intake
Fwi = Fender wall intake
Hai = Hot air intake
Alky = Alcohol injection
Lim = Lower intake manifold
Cat = Catalytic converter
Cam = Camshaft
Plog = Power Log
Maf = Mass air flow
Dp = Downpipe
Pcm = Powertrain control module
Wizaired = A cold air intake namebrand
Hud = Heads up display
Kr = Knock
L26, L36 = N/A engine types
L67, L32 = S/C engine types
P&P = Port and polish.
I will add them when i think of them. If anyone has ones to add be sure to leave them here.