the thing with sound quality is, you can have the most expensive, amazing head unit on the market, and still have a crappy sound system... i have a clarion head unit (pretty high end of the line), and its awesome... but i dont use it to its potential because i have a cheap amp... i guess the thing is i can get everything out of the amp with a good head unit... the point is, i like clarion units, and i have heard good JVC, and Pioneer stereos. I'm actually yet to hear an alpine head unit in person! But they are known for their quality. and with the spacers - SHOP AROUND!!! I was ripped off by Pennant Hills Toyota - $30 FOR THE SPACERS!!! Friggen hell what a ripoff! I was in a rush to get them cos I was dying to get my system in when my head unit arrived. I ordered mine on ebay - got it for about 65% of the retail price, with shipping, but i dont get a warranty... so im hoping it wont break in the next 9 months or so :P .. in my opinion, its worth getting something online, specially on ebay, cos you can get it WAY cheaper... but you gotta be careful and you're taking a risk with the warranty...