ok first off 17 volts isnt impossible. its high likely but your altenator will fry within the week beleive me my laternator was charge at 16 volts ebcuase it was a refurbthat wasnt set right. it was toast i na week. as for find out how to birdge the subs jsut go to this web site
http://www.rockfordfosgate.com/rftech/wiringwizard.asp put in what you have and it will tell you what your options are wiht yoru set up. its universal so dont worry jsut becuase its the fosgate site.