[JivenJim]

Glad your liking the S.
How big is your wallet?

Here’s some of my very, ball park numbers

Cam reworks ~$1200 = 20 hp
Lighter/faster valve springs ~$1000 higher rev and works with Mod Cams
Over bore to a 3.4 Liter and sleeve ~25 HP $1800
12:1 CR JE Pistons Required for over bore ~ 15 HP $1200
Good Clutch and maybe lighter flywheel $1500 +
New Front and rear seal kits.
Gaskets for everything
Electronic ignition management $600-3000
and maybe knife edge the Crank if your going to race it. $700

Also a great time to replace all those vacuum lines and gas rubber lines.

Yep it's gonna cost a fortune to do right, which is why most people just give the car the min it needs.

Kinda surprised you didn't go right for the money shoot and ask how to turbo the 16V! Sorry for the ribbing. It's asked Alot around here.

If you’re just going basics:
Valve seats, guides, and new Piston Rings are standard rebuild stuff.

Hope this give you some ideas.
Do searches on any of these items and you’ll get lots more info.
Ask back if we can help clarify.