Windshield is not hard...even I did that...(with the help of a friend , 4 hands better than 2 doing that!)
I'm sure you didn't beat my $150 price,(?) so it boils down to what kind of glass your 4 hands will be on. Round(bottle) or flat(windshield).
I bought w/s locally $140, installed self ,but paid $18 for the "caulk"...
$158 OK I'm already a six pack up on you before you started! LOL
I know....they would have done it installed for $145, but I /we just wanted to make sure no leaks....so I didnt have to go back....so it cost me $13 MORE to do it myself vs them ...but I saved on gas ,not going back....and I did NOT stay at Holiday Inn! lol
not had any issues with the w/s....but it still leaks abv it ...lol