The stealth box comes with I believe a W6, so all you would need is an amp. I would get at least 400 watts.
Install of an amp is pretty straight forward but you will need to get a remote turn on lead, output converter, and RCA's. My suggestion is to get an amp like MTX with Smart Engage and speaker level inputs. Many manufacturers and jumping on the factory intergration bandwagon since some cars cannot lose the factory radio without messing something up. Anyway, the stealth box is I believe $695 or so from Crutchfield and you can get an Alpine amp for less than $200 there too.
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