Stiff Brake, Jerking, and more. Your help is very much needed!

Thank you for looking. Your help is much is much appreciated.

I have let my pony sit the last five years.

All I am looking to do is improve my car so it runs smoothly on the street (no racing)

I have a 95 Mustang GT with the following:

GT 40 Crate Motor with E303 cam
Trick Flow upper and lower intake
Automatic Transmission (rebuilt) w/ 2800 stall converter
30lb Fuel Injectors
Upgraded Mass Airflow Sensor
Cool Air Intake, exhaust, etc...

All of the changes were made at once, and the vehicle has been sitting since.

I am having the following issues once I made the changes above:

Stiff Brake Pedal when RPMs are low.
Vehicles jerks when iddling or moving slowly (little RPMs).

I believe the following additional items are needed: Larger Fuel Pump, Throttle Body, Adjustable Fuel Pressure Regulator

I have a few questions:
-Considering I had a 2800 stall converter installed with upgraded transmission, shouldnt the vehicle sit still with a foot on the brake and a foot on the gas at low RPMs?

-Do you have any suggestions for additional parts that are imperative?

-Do you have any ideas or thoughts regarding the stiff brake pedal or vehicle jerking?

-Any suggestions on mechanical help in the Chicagoland area?

Again, all I am trying to do is get the vehicle running smoothly to drive on a daily basis.

Thank you for your help. It is much appreciated!

vacuum line have been checked with no problems.