I just finished installing my own solar array. The faceplate wattage is 6,240 w, so pretty similar in size.
My cost numbers were comparable. I paid less than $12,000 for all the equipment and installation. I used Enphase 215 micro-inverters, but as others have said, I think the micro-inverters and optimizers are pretty comparable right now. Both will give you the "rapid shutdown" and some other advantages.
My system should cost about $6,000 after incentives.
I've also ALREADY been driving an electric car for some time. (Mitsubishi iMiEV right now and a previously a home conversion Geo Metro and electric motorcycles .)
Solar and PV go great together.
I've also figured my simple economic Return On Investment at about 6 years.
I have also run the numbers in several different ways to include making one's own motor fuel through photovoltaics for an electric car in place of purchasing gasoline. Depending on how you look at it, that can bring ROI down to 3.5 years.
Nice job! Your PV system looks great!
I also just got my first electric bill which included a COMPLETE month of solar production. It was a $40 credit!
First SOLAR Electric Bill
Here's what my array looks like. The white car is mine, the blue one belongs to a friend who was visiting.