oh yeah, dont buy an EQ without a line driver, thats just asking for noise and distortion. When you start boosting frequencies without the additional power in the signal, you'll run into problems and probably do more harm than good for your music. Once you choose one, its all a matter of properly tuning the unit to your deck and amp(s). If you can, have a local shop use a RTA to actually "tune" the EQ, they'll probably just charge you their hourly labor rate (so figure about $60). If you do it yourself, which by all means is possible, just throughly read the manual and make sure you understand what all the knobs actually do before tuning anything. Improper tuning will lead to noise and poor sound (like a metalic sound), and possibly damage your speakers if you're really careless.