Well, I'm waiting for a couple more bids, but the best one right now from a company I trust (they did my first array) is 4.52/w. I googled a bit more and found a site that listed installers and "average" cost/watt of installs, but didn't give a timeframe for that average. On the bright side they act as a referrer and I was able to find a couple of additional candidate companies. I'll end up with 4 bids by time this phase is done and will then be able to move on to comparing them.
What size is your new array? I'm assuming that there is some economy of scale that would effect the price per watt. I can't decide whether to pursue more bids. It seems like I should before spending $20k+. But on the other hand it appears that the quote that I got is very competitive on a $/watt. I don't know if I've seen lower than $3.28/watt installed (pre-incentive).
Also, are you going micro-inverter or string inverter? String inverters appear to be cheaper and I think that I like that approach better if you aren't dealing with shading.