Re: Door and window seals ?
Re polish, I'd go for Maguires, reasonably cheap and effective. Be careful of some as they have fillers so although when polished look good, don't actually remove your minor scratches! (Some Maguires have fillers too). As they fill they need constant polishing, every week or so, to maintain as with a few washes you can see that the shine tends to dull slightly again as the minor scratches reappear as the wax fill is washed away. (This isn't too bad a thing as I reckon once a week is not too much to give the car a good waxing anyway)! There are a few links here that look at this a little.
Quick detailing (Maguires do one of them too) with a clay bar, remove all dirt and inbedded grime, then a good polish and waxing. (There's a 3 step package around at local stockists). As long as you keep it up you should ensure that your finish remains constant and your colour doesn't fade. Last Alfa I had was red, 145 Boxer 1.7, and I found the paintwork was immaculate and never faded but ya have to look after it! :-)
Autoglym also do some good products at reasonable prices. There are many that you can pay a small fortune for. All depends on how far you want to go.
Hope this helps,