I called two places one quoted me 170 the other 230. I was wondering if the front windshield had any variation. Does auto dimming rear view mirror uses another front windshield or they all the same?

 

I've had to replace my window twice, the difference in price is mainly due to the quality of the replacement they're offering you.

Usually the cheaper windows are crappy chinese glass. Honestly, I made that mistake once and I seriously regretted it. The glass pitted very easily and didn't last.
The 2nd time I had it replaced (because I was sick of the pitting) I took it to Safelight and theirs has been MUCH better

the only real difference I noticed was the top center of the glass where it's a darker color