Howdy, my wife and I have one of the oldest westgates in Milton so I imagine upgrade prices are double what we paid ; )
I agree about hardwood after closing unless you want it in the kitchen then get the builder to do it. Ditto on the backsplash, if you find laminate that you are happy with delete the back lip so it is more of a butt joint with the wall then the backsplash looks far better.
For potlights the best bet is to have mattamy install and extra switch and an extra box then just punch the box out, replace with a pot and run extra wire for the rest. Usually works fine until you find a red plastic pipe in the wrong spot
My biggest change was tearing out the main floor closet right after closing. Was a huge job and was kinda scary on a brand new house but the results rule. The basement door, closet door and garage door are a total gong show on the model so removing the closet door and a small wall opens it up awesome. We put in a bench and a wall cubby with hooks and it works well. Its been done for a couple years but I am too lazy to put pics up. Maybe in 2011...
Have fun, enjoy the Westgate and fight for both sets of stairs on the porch!