Back half maintenance and cleanup of my 97 GTS Tips needed

[AviP]

I've driven my GTS probably less than 2000 miles in the last 6 years and as a result have not maintained it as well as I should have. It's also bone stock for 21 years (original owner) but I'm open to changing things now. Never say never!

So that said, I plan on working on the underside starting with the back half. My questions are :

1. I'm thinking of upgrading the rear-end, perhaps 3:55 or 3.73?
2. At my last tire change, I did a wheel alignment and the spec showed my driver side rear wheel was slightly off spec. Darn potholes happy NY/CT area. I seem to remember reading a while back that the chassis does show signs of age in pothole country. What are the remedies?
3. The shocks have not been looked at in 20 years and I'm wondering if I should look into upgrading, springs, etc. What options have worked best for people here?
4. Should the bushings, u-joints, axle seals(?), etc be replaced?
5. I think I'll stay with the same half shafts because I don't anticipate any major engine upgrades.
6. I do want a louder exhaust but that will be later when I start working the front half, so I'll leave that for a later post.
7. Any cleanup tips for rust, chassis, suspension, bolts, etc. will be appreciated.
8. Talking nuts and bolts, does anybody know of titanium options.
9. I'm upgrading the brakes to Ricks (Toms) 40mm pistons. I want to do both front and rear brakes lines in stainless steel. What are the options?
10. Fuel cap aluminium is showing signs of corrosion. Is this a simple fix : remove, sand, polish, clearcoat or more involved?
11. My polished wheels have lost their shine and show minor corrosion but in many spots. I'm tempted to DIY fix it. Please tell me to farm it out to a professional.
12. Any interior upgrades in the trunk area.

I know that's a lot of stuff but please don't limit yourself to these. If there is anything else related to the underside rear half, I'm all ears. Also, I'm an average mechanic and I tend to learn on the job. Can't say I always get it right but given that I live just 5 miles from Chuck/Rob, he's saved me when I've been up to my neck.

Thanks.

[C5Longhorn]

I did my own wheels and fuel cap. Since it's not a daily driver, I stripped the old clear coat off, sanded, and polished. I haven't recleared, but may do that down the road.