I am installing a cheap aftermarket radio. My understanding is that the wiring harnesses for sale do not connect to the subwoofer. I know there are fixes for that and I have read the articles.

My question is what do you do if the new unit does not have a line level output for the subwoofer?

Can you use a "Y" connector to split one of the line level outputs for the speakers, stick a crossover in the line and then run the wire to the subwoofer?

Would this work?

http://www.ebay.com/itm/Single-Power...torefresh=true

 

Or maybe this one ...

DC 12V 24V Low Pass Filter NE5532 Bass Tone Subwoofer Pre Amplifier Preamp Board | eBay

 

Return the "Cheap" aftermarket radio and spend a few bucks more on a radio that does?

Or

Get a line level converter (converts higher power speaker input) to low level RCA

 

If you already bought the unit and it does not have an option for the subs, chances are it would not be able to handle an additional load such as subs. I definitely would not buy any of those eBay deals you posted. What head unit did you get? That would really help as far as finding solutions. I ran into the same issue as well when replacing my system. I just bypassed the whole bose system and am replacing everything, besides that stock system is garbage.