The 12" Type Rs has a max rms rating of 500 watts. Getting a 1000 watt amp is asking for a lot of power from the alternator. You probably should be shopping for a SUPER efficient amp, or getting a less power hungry sub. There are a lot of subs out there that does pretty well with only 300 or so watts.

IDQ from Image Dynamics
IDv.3 from Image Dynamics
W3 from JL Audio
13kv from Elemental Design.

Just to share something, at max, I had 1200 watts going to my system. I had 2 4g power cables running from the battery to the trunk. Although this is not a huge system, it put a huge strain on my alternator.