Lest expensive set of monotube shocks/struts for 94GT?

If you want a monotube, Bilstein is the only choice. Everything else you listed is a twin tube. I personally have had two sets of Bilsteins on my car. I replaced them with a fresh set when I got coilovers.

Food for thought... if your name is an indication of your profession then hopefully you might like a little tech on the subject before making the decision solely on price. You get less aeration in the oil in a monotube since there is no gas exchange between the the chambers. Furthermore, the tube and strut shaft are more robust. It is really not that much extra money and struts and shocks need to be replaced regularly so it will probably cost you more money in the long run to get the cheap stuff now. If you can dig around, you can try getting 03-04 cobra front bilsteins to save money and then just buy bilstein rears.

By the way, you do not want Fox struts. They have less bump travel. Most SN95 ones have internal bump stops too. Foxbody guys that are serious usually run SN95 shocks and struts. I am pretty sure Maximum Motorsports will not even sell you Fox ones, they just give everyone the SN95 style since they are the same price.

The only real factor that makes a shock or strut stiffer is the valving. Keep in mind that everything I say should be taken with a grain of salt because my daily driver car has 400 lb front coilovers so my idea of streetable is might be different from yours.

My car had blown shocks and struts when I bought it so when I put Bilsteins and H&R race springs with 390lb torque arm springs on in the rear, I thought the ride improved. I think the 03 cobra stuff is too soft for me. I honestly find the budget stuff like KYB GR2's rides like total crap because it they feel underdamped and the car feels bouncy or bottom the struts out on hard bumps.

I would base this decision on what springs you want to buy. I usually do not post on these boards because I generally have an opinion well outside the consensus, but I would really only recommend two setups that run conventional springs. For guys that want a soft ride 1:Bullitt suspension and are the next step up 2: H&R race springs with Bilsteins. Neither of those options will really lower the car as much as it sounds like you want so it is up to you.