MyScRuNmIa

Hey my qustion to all of you is this? my babie is a 94,sc400 with 200,000 highway miles so far all i have done is upgrade the audio system. next im looking in to performance mods an i just wanted you guyz to let me know. So far im looking into purchasing a s-afc, a larger fuel pump,a cat back exhact system, i wuz told to leave the intake system stock an just drop in a k&n air filter, is this true by the way..? by the way i wuz also looking at nos, if i did how much could i use, an should i do a wet sytem or dry. from the mods i have listed here plz let me know how much more power i should gain. wud it be enuff tto get in to the low 14ec 1/4 mile times. Also lsd,dose my car have it or not cuz sometimes when i light them up both let loss an sometimes only one dose an drag radials an a torque converter how much of a difference do they make..?