intake headers exhaust

i have a 94 ls, its completely stock, the only thing im gonna do to the car is i/h/e plus a racing cat because the motor already has 170,000 miles on it and i want it to last as long as possible, plus im broke and cant afford to do any major engine work, im curious about 4-2-1 vs 4-1 and was thinking about a larger throttle body. Im also wondering if the throttle body upgrade is unnecessary and just a waste of money, the car is an automatic and isnt slow but isnt very quick either, i just want the car to be a tad faster, im not planning on doing any kind of serious racing just the occasional match up here and there on the road. Another thing ive noticed is my car tops out at about 110-115, itd probly go faster but it already takes at least a minute or two to get there and im not trying to have a criminal speeding ticket, ie id like to improve the top end. Which combinations of i/h/e will work best for what im trying to accomplish?

A bigger throttle body won't give you much of a gain unless you have an aftermarket intake manifold also.

im planning on the intake manifold and an aluminum radiator, probably fluidyne, too, the post was kinda long and i left that out

Supposedly the 4-1 header configuration gives more top end power than the 4-2-1. Never owned one though. With the racing cat, that might help your top speed situation.

Convert from Auto to Manual it would be the best upgrade even for the "occasional match up"