Spacers are plentiful and easy to find.

 

x2

spacer should be used regardless.

You don't want the speaker on bare metal

pick one
http://www.ebay.com/sch/i.html?_nkw=...at=0&_from=R40

 

I have used Alpine for years and they make great speakers, amps, and head units. Here is a set of all in one that are just over the budget, but well worth the extra spend. Just sucks they are out of stock. If you can find last years model; listed on the same page, you would be in good hands.
Alpine Type-R 6.5

Now this componet set would be worth the extra for the front so you can set a better sound stage.
Alpine Type-R 6.5 Comp.

All in all eveyone will have a brand they love and recommend. A really good way to pick what you like is to go to a local shop and listen to their display's setups. Everyone has their own "taste" in how they want something to sound to them. One brand may be two bright compared to another and you need to hear them to make sure you like them overall.