common mis-conception......
a 300W PSU does NOT mean it will draw 300W, but can handle upto 300W of load...
for example I have a 300W PSU and only a 140W inverter running in my setup of a Duron 800Mhz/40GB HDD/5.6Inch TFT.... thus the mp3car setup obviously draws less than 140W and ALOT less than 300W
good brand of inverters?? wouldnt know..... I got mine from
www.jaycar.com.au in Australia, but thats prob a little use to you!