Invasive sound at the front can be corrected if you have the appropriate controls on your head unit. My Pioneer DEH9600 allows you to centre the audio front to back, left to right, so you can get a perfect sound for you. Obviously for this, you shouldn't go sticking very powerful speakers in the front and crap ones in the back, it's all about balance. Also, you may want to move the speakers to the door instead of the dash, so the sound goes into the car and not into the floor. As for running speakers without an amp, what? lol. You're more likely to wreck speakers or the HU by running them off the HU directly, as the HU usually only supports around 15w RMS, and uprated speakers demand much more. I had three amps in my first car, two cheap alpines that did 2x90w or 1x250w for a sub, and a 1100w sub for 2 500w subs that I had. The whole lot sounded wicked, but it's extra weight and the whole lot is sitting in my roof now. Edit - something like this would do some 6x9's or front speakers, and is similar to the ones i've got. http://www.ebay.co.uk/itm/Alpine-MRP-T130-Car-Amplifier-/121087748224?pt=UK_In_Car_Technology&hash=item1c31646880 - Just search on ebay for Alpine MRP and loads come up