windshield install

How hard is it to set in the windshield and rear window? I have the glass and rubber gaskets and sealer. New trim clips have been installed front and back.
I've called a few local glass companies and the cheapest any one will set them in is $150.00 per window. Is this something I should leave up to the pros? or can I do it myself and use the $300.00 to get my duel exhaust put on.