I was thinking of putting in some subs in my bonnie, but i do not want to change my factory stereo (top of the line cd-player with equalizer plus steering wheel controls). I have seen some powered bass tubes that let me hook it up to the back stereo wiring. Are they worth it? Also how will a bass tube sound in a big car the bonneville?

You can hook any kind of sub up to a factory radio. The only downside to that is if you turn it up loud. Once you get to a certain volume, your factory radio will start defeating the bass.

If you do that go with the 10" 300w Pionner Powered bass tube sounds great in a bonnie

i hate to be the one to break it to u but ne thing out of any car is junk when it comes to stereos. the best setup is to replace it all i know its expensive but i can get u some deals my stereo installed is worth between 3 and 4 grand and i paid about 700 for mine almost all new u need to use ur front sound stage for highs and midrange and ur trunk for the bass. get a good deck and a good amp for ur highs then take out the back 6by9s and have ur subs upfiring off of ur rear window. email me for more info.