We usually look a prices after the STC rebate. You could most likely get a cheaper quote. But the important thing is spending the right amount of money to get a good quality system installed from a good company. We always recommend getting at least a couple of quotes so you can compare though. That way, if you do really like this particular company, you have something to negotiate with them on.
Sungrow are a really good ‘value’ inverter brand. Basically, the best of the cheapest in my opinion. Canadian Solar is a decent quality mid range panel, you can see a bit more on the BiKu panels here: