if the only change in one of my chips over stock was to change the constant for FI size from 22 to 24, and the car was to feel slower, where would i first check into the issue?

 

You have to look at the parameter you are changing with an expected output change.
If you upped the injector size in the bin it will cause one thing to happen for sure.
The pulse width will be less for a given calculated output
(bigger injector does not need to be opened as long as a smaller one to get the same amount of fuel)
You should have seen the PW drop slightly for the same load point. With that being said your BLM will have changed because the amount of fuel for the same load point has changed. The calculations in closed loop will correct for the difference and you'll be able to see something that correctly responds to your change.
Whenever you make a change you should have a fairly good idea what to expect from it or you are shooting in the dark. It easy to go in circles like that.
Plan your changes and look for the result, if the result does not appear correct then go back and rethink your strategy. It might turn out that you are changing the wrong parameter to solve a problem.
HTH

 

im not trying to solve a problem, i really have 24# injectors, and i just wanted to correct that in the ecm accordingly.

 

Thats good to get things where they belong
Do some logging and begin working in the VE tables (or whatever they are called for you MAF) I'm mainly an SD guy so I'm not much help with MAF tuning. Go back to your baseline spark tables, You should see the problem with fueling quickly with some logging. Work the BLMs into shape then play with spark.
Back to the stickies and tuning guide for you
You'll just have to keep driving around and tuning until you get it feeling better at this point.

 

Are you getting knock counts with the gear drive?
That could be a big part of your problem.

 

i dont have access to datalogging til this weekend so i dunno, i doubt it though, lots of people here have admitted running a quite drive for quite a bit of time without any knock.