I've been looking for parts that could increase hp and make it louder. The only thing i could find was a glass pack and an air filter for my freakin '01 s80. I heard that glass packs dont provide hp but they make a car sound luder. Is there anything else i could add to it?? (im low on cash btw)

Have you checked my post in the General section Links to sites?

Is your s80 a t6 or just a 2.9L N/A?

If it is turbo there is more you can do a lot more.

If your N/A don't bother. Just stick with apperance modifications.

You can check some online and local stores. They might have volvo s80 parts (http://www.swedishpartsshop.com/volvos80parts.html) available.