Do some measuring of the steering box on the S10 frame. The s10's are front steer and the box may get in the way of the fenders when you put them back on. The F car subs are rear steer and the box isn't a factor for fender clearance. You may want to look for a 2nd gen Camaro/Firebird/Nova front sub to solve ALL of your problems. Another option may be one of the full framed mid-size cars. 4th gen Monte Carlos, Grand Prix, Cutlass and Buick Regals have a fairly wide stance and may work for you also.
The rear track width can be adjusted with rim offset but the front is another thing. You don't want to push the wheels outboard to far because of bearing wear and bump steer that is induced by the increased lever arm of the offset wheel. Keep the track width as close to stock as possible in front (a little wider won't hurt anything)