[Mach 1]

Well, you have to do what YOU want to the car, but Ill throw my .02 cents in.

I like and strongly recommend mass air conversion, especially if you want to play with cam changes and tuning.
Its simply superior to speed density, although youll hear differing opinions about that here.

I agree with 82GT about the 3.73 gear ratio. Its a good all around choice for a 5 speed.

Replacing the bearings is a gamble. They might last a long time, they might spin tomorrow. Your gonna have to make the call on that one, however if you know they are damaged, you probably should replace them as soon as possible.

As far as suspension, get welded in subframe connectors as a minimum if you dont have them already. After that, it all depends on how much coin you want to drop, which doesnt sound like much, so I wouldnt worry about it that much. I do like aftermarket lower rear control arms after the subframe connectors.

I dont recommend 20w-50 eithier. get the sludge out of there and get some oil that can flow in there. If you are having low oil pressure problems with your high mileage, a higher weight might help some, but there is really no reason to run it. Use the oil recommended in your owners manual, which is 10w-30 for your engine.

Save your coin on the BBK cold air kit. It doenst fit well, the chrome flakes off easily, and its more for looks than anything. The factory setup with a k&N panel filter is just as good. Or get the moroso kit. better than the BBK and cheaper.

Rear disc brakes are nice to have, but I think you could concentrate your performance dollar elsewhere for better results. My stang stops fine with the rear drums. Always has and always will. I dont road race though, which you mentioned you are interested in, so it might be something for you.