Headswap labor depends on who you talk to and how big their shop is!
I charge $650 for the headswap. Complete engine swap would run $450.
Porting on the PI heads is $400.
You do not use the '99 & up ECU. You use your stock one. Simply use your existing wiring harness, fuel rails, exhaust, etc, etc. It's simple. One other thing to remember. Swapping the PI heads onto a '96-98 engine will give you 10.3-10.6:1 compression. Adds some power! The '99 & up engines are 9.1:1 compression. The make good power as they are. It all depends on the condition of your existing shortblock and/or the condition of your checkbook.
Let me know if I can help!
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SD Wheeler
M/M #30 '98 GT
Strictly Performance
MV Performance
"The Game"