Tap a power source

alright, I have a bass tube to install with built in 200 watt amplifier. I need to run a power wire, I can either run it to my battery, or I was thinking I could tap the signal coming from the 12v wire going to the Head Unit. what are some suggestions, if i tap off the 12v going to the HU, am I going to mess that up, since I have to tap off the speaker wires coming from it anyway, I was thinking that would be the best way, and then I wouldnt have to run my power wire into the engine bay.

Please by all means do not tap into the headunit 12 volt! I ve been installing car audio and alarms for 3 years now at tweeter and circuit city. Alway go to the battery that 12 v wire going to the head unit will not bea strong enougn source and one of 2 things will happen . One and u better use a fuse and holder(no exceptions ) u will constatly blow your fuse for the bass tube and your radio . If you dont use a fuse u will start a fire . I know going to the battery isnt easy but if your have an automatic look for the cut out of wear the clutch plate would have been aand drill there . Always double drill verify look twice, drill once. Or im sure you have a gromet to go through .