I have 2000 I30t. I got amp and sub
5th gen bose amp diagram
zerothread/157919 if u using mono amp for sub u should be able to pick preout inputs(either both front or both rear speakers) that come into the bose amp. if u use line converters that are mentioned in the previous article the preamp in lines might not work the signal might be to low then u would alternatively tap into one pair of output. blue on/off sub amp wire can be connected to 25.
If i get line converter i was thinking if im able to get something for the small wires like low voltage push in connectors then ill use that.