I have been doing a bit of research and I think I have found a setup that will work but I just wanted to check with some other people to make sure I wasn't missing/overlooking anything.
I have a lap top without any line out so I will be using a Fiio E7 that I already have (http://www.fiio.com.cn/product/index.aspx?ID=28&MenuID=020301) as my DAC/Preamp (its plugs into the laptop via usb). Now for what I haven't bought.
I will take the output from my E7 and run it into the actual amp/crossover (http://www.parts-express.com/pe/showdetl.cfm?PartNumber=300-803) mids/highs will be sent to a pair of book shelf speakers (http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=300-652&scqty=1) while lows will be sent to this driver (http://www.mcmelectronics.com/product/55-2421&scode=GS401&CAWELAID=220564908?cagpspn=pla&gclid=CJ_T-qeyiLICFUhN4AodglgAcA) which will be in a subwoofer cab that I am building.
Is this a workable setup?
Should I go with a lower power amp and still get the driver to really move?
How do I make sure that my bookshelf speakers which are lower power don't get too much wattage?