I have a custom steel bike (89) that I really love. It's campy chorus & athena (all original) and running a 7sp. I'd like to upgrade the drivetrain to 8sp with shifter brake levers. As I don't want to dump a ton of money into the bike I was thinking of purchasing campy 8sp mirage shifters & a rear derailler and an 8sp casette. Is there anything else I'd need? Do I need to change the front derailleur? Aren't the campy front derailleurs friction based.

I don't think I can go to 9sp because I'd have to replace my rear wheel which I don't want to do. Currently I'm running a 7sp cassette with a spacer on an 8sp hub. I assume I can't put a campy 8sp casette on a shimano hub, right? Any reason any 8 cassette wouldn't work with the campy?