Water pump pulley may be different
Some came with different valve covers
some had the aluminum cross over for the intake and some didnt(mine didnt)
Most of the difference came during March production of the 01 PI engine.
That is exactly how it should happen. PSI is showing resistance, you now have more flow(CFM) going through your heads. Your PSI will be lower but your power will be higher.
Here is my honest opinion.
BBKCAI=junk
BBK= its ok, Trickflow would be better
Ford intake is just a stock PI intake
Flows + X pipe sound like :poo:.
You'll be in the 14s.
New Kmember
Tranny cross member
Different transmission(bolt pattern isnt the same)
driveshaft from a 94-95 mustang
fuel lines(99+ doesnt have a return line)
power steering pump
brake system from a 94-95 stang
Im probably missing a lot....
IMO you have few options.
1. new body
2. cut front end off and go with a tubular frame
3. spend time and money getting the front straighten on a frame machine