2nd amp

Getting ready to add a second apm to a vehicle and have a couple questions.  Currently running usx2050 160 total watts.  Have 8 guage power and grounds.  Going to add a power distribution block.  Looking to add another a amp for sub somewhere between 150 and 300 total watts.  Will the 8 guage power wire be ok?  I currently have a 40 amp fuse after the battery do I need to upgrade that?

Will a 150 watt rms sub produce decent bass?  Probably looking at a 12" sub in a sealed box.

I think your 8 gauge should be fine, too, because I run a setup similar to that in my car and the 8 gauge is plenty.  I also use a 40 amp fuse on the power wire, but the "real" rule for fusing wires is to use a fuse that is rated for the wire gauge....not for the amplifier load at the end of the wire. 

And you should be looking for close-outs of decent brands with that budget.  Try to find a 12" with an efficiency factor that is pretty high, around 90 db/ 1 watt...and a mono sub amp instead of a two channel.  You'll get the most sub volume for the least amount of power consumed when you're talking about a 200 watt and below range.  And you can still use a sealed box 1 cu. ft. or so.  Choose either SVC 4 ohm or DVC 4 ohm sub depending on the amp you find and its power output rating.

Ok would the effeciency factor be what is called sensativity on the spec sheets?

I think I am looking at this combonation:

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?Productid=12353

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?Productid=13948

Unless I find something cheaper.  Only question when they give the bridged amp wattage at what ohm would that be?