I could comment on two of your concerns.
Repair manuals :
CD-Rom > go on ebay, got mine for $12, my computer crapped out so I can not load it. Manual, I think mine is haynes (teal green). My only complaint has been that sometimes there are detailed instructions without illustrations, and you are suppose figure out what the doodad looks like and which doohicky it's connected to. Go on ebay and get a parts list for about $5, this may help in identifying parts.
Exhaust:
I had mine replaced 2 years ago with Walker parts.
Completely rotted out in 3 places. The Muffler was so bad, I couldn't identify the serial number for the company re/the warranty because the shop did not indicate it on the receipt.
Another board member advised that the condensation that builds up in the exhaust is the culprit. ( ever notice water dripping from the tailpipe?)
I was only driving about 4 miles a week, and it did alot of damage.
If you plan to keep it, I heard that they have stainless exhaust, do it once and forget it.
email me if you have more questions.

1990 780 Bertone 167K NYC