What is the best and most cost-effective way to maintain and improve the performance of an Audi 80's engine?

I recently purchased a used Audi 80 and I'm looking for ways to keep its engine running like new without breaking the bank. I want to know what maintenance procedures and upgrades can be done to improve performance without spending a fortune.

Regular oil changes and using high-quality oil is key to maintaining the engine's performance. Additionally, upgrading to a cold air intake and performance exhaust can give your Audi 80 a boost without breaking the bank.

Invest in a quality fuel additive to keep your engine clean and running smoothly. Changing spark plugs and wires every 30,000 miles can also help maintain performance.