Paint sealant: Good but a waste of money. Just become friends with the detail guys and they can apply as many times as you want, whenever you want..wink wink.
Tire Repair: I assume they are speaking about flats etc. I only use PS2's and purchase through Wheel Werks. They match prices, such as the low prices offered from TireRack, and they offer tire warranty for $50 per tire. I can't tell you how many flats I've had here in SF, probably 3 to 5 in the past year, that resulted in punctures that could not be repaired. Their warranty stepped right in with brand new tires every time.
Also, i've had sidewall bubbles plenty of times on my PS2's and the manufacturer's warranty covered these(caveat, unless your tread is worn to a certain depth). I recently had a side wall bubble that was past the manufacturer warranty spec, in which case the tire plan from Wheel Werks covered this(caveat, unless past the wear bars).
2008 E92M3-Space Gray
Eisenmann Sport Exhaust_MT/Loaded