You need V6 specific springs. GT's have a higher rate in the front (more weight).
I would look to Eibach or H&R and make sure you get springs for a V6.
It should sit like this....
90 LX, Previous 4 cyl.
408W In the Works
TW FAC's, Jay Allen cam, Super Victor 2001 V6 5 Speed Daily Driver
Windstar Intake, Dual Exhuast, CAI, Headers
Best ET: [email protected] mph (on 18's)