Do it yourself spoiler mounting, window tinting & emblems

Does anyone know how difficult it is to attach a spoiler yourself? I'd like to add a small spoiler to my IS 300 and from what I heard a lot of the Lexus dealerships actually outsource this to smaller shops. I've also heard that those shops buy the same actual spoilers that are the the factory Lexus's, at least for IS's. Any advice?

Also, thoughts on a do it yourself window tinting job.....besides spraying on a lot of water and making sure you squeegie (sp) out all the water and airbubbles?

Lasty, I need to put 2 emblems on the trunk. Any advice on the best way to allign them?

Thx