The reason I say it will be a mess is because with a 4 link, crappy
control arms, shocks and springs, no subframe connectors it will be impossible to keep pointed straight.
Even in their best form, stock brakes and drums are only good for a couple stops.
If you run good tires you are sure to break a t5, if you don't run good tires you will be going nowhere fast.
Foxes are light and loose, 450hp magnifies that.
Me? I'd go for 94/95 spindles, wheels and tires and discs in the rear first.
If you want gears, do them at the same time the rear is apart (a gear change adds the most fun factor for the money)
I wouldn't put a dollar into 4 lug anything and I pray to never see a drum brake ever again.
Then i'd get real familiar with the maximum motorsports catalog, starting with subframe connectors.
If you want when you do the brakes and go five lug, do an IRS if that makes you happy.
Seems like you had the car for quite some time so you aren't going to get rid of it, go all high end parts, you won't have any regrets.
If your current engine doesn't burn any oil, I also see no reason why you have to go from 200rwhp to 450rwhp.
Consider working on the
suspension and brakes and installing the Paxton.
Or if you like do a nice h/c/I setup.
300rwhp can be a blast in one of these cars with a good
suspension (I like the road and track kit, except with front coil overs).
Trust me, an extra 100rwhp (one third more for perspective), is quite the bump in a 3200lb car.
The beauty of a fox back in the day was that you grew with it. A couple bucks here, a couple there and after a few years it all adds up to a really nice package.