03 Passat - general questions

Hi all. I just bought a 2003 Passat on Tuesday (1.8 GLS). I had fallen in love with this vehicle a year or so ago and just had the opportunity to buy one. I have a few questions and don't have the owner's manual yet. Can anyone help out?

I was told to only use premium gas. Is this a must or can I go with mid-grade (89 octane or better)? Is it an engine performance (overall) issue, a mileage/efficiency issue, something to do with the turbo or a warranty issue?

I seem to remember the dealer showing me that you could change the color of the dashboard lights, am I remembering right or am I nuts?

Also - any general tips for a newby for getting the best care/operation of my car?

Thanks!

wiring problem , 1995 passat GLX TD. Fuse # 21, when installed turns on engine monitor lights "oil pressure ex. , interior lighing will not work ever, even when any door is opened, but all interior light s work manualy,clock keepalive doesn't work, power locks only work when fuse #21 installed, fuse is a 15 amp which will blow , a 20 amp warms up but no damage to harness as yet cause I pull it out after 3 minuets, I did see the right rear interior light glow dim once I think from a dooor being opened, I think cig lighter is in on this deal

You can get a factory manual here:

http://www.bentleypublishers.com/product.htm?code=rp03