Make sure that IF you cut off the plug for the cigar lighter, you put the same size fuse (usually inside that same plug) in line with the inverter. This is a safety thing... don't skimp.

In my case I got one of those double cigar outlet extenders (with cords, not the plastic casing ones) and wired it directly into the heated seat hot line behind the heated seat controls. I then ran the cable under the center console to the rear where the inverter and the plug/outlets sit behind the seats. With that circuit you can easily run a 700 watt inverter. Make sure you get a chassis ground for the other side of the line.

Good luck!