I'll Ditto on 80K miles are ok, that just means the car was actually daily driven, not babied.
My car had a similar vibration at speed, and I have the stock 2.73 gears still. The vibration was felt through the shifter handle, with a aftermarket shifter there is no rubber insulator so you will feel it worse. I figured it was probably a out of balance driveshaft combined with tired ujoints. The FMS aluminum driveshaft was only $160 for my car, a few bucks more for 94-95, and the vibration totally went away, worth it big time.
As for addnl mods, new headers and H pipe help out. Switch to a cold air intake, larger Mass airflow sensor, throttle body.
If you want more, new intake, heads, cam, stroker 347, NOS, blower whatever you want to spend
Start by fixing the vibration,get used to the car and slowly make some minor mods
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Frank W
90 5.0 LX coupe Daily driver. K&N filter. Flexalite fan, 3 core radiator. FMS flywheel and Clutch, FMS blue wires Energy Suspension end links, MAC 2.5" cat back FMS aluminum driveshaft, MSD blaster coil, MAC shifter
88 Notch 2.3L FOR SALE!
My two Notchbacks
74 Chevy Laguna Type S-3 305 Finally fixed getting a 454 to put in garage
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