One time,  we came upon a job at a Body shop.  The Windshield install was not original and there was so much rust.  The rust was to the point that there were holes in the body of the Toyota.  Saving money at the time might not be the best solution; consider your options.  Ask the question of who is installing the Windshield ahead of time.  Do they prime the metal, glass, etc.  Are the sealants of high quality or is this a lick it and stick it job to your installer.  A high quality install, though initially it may cost you a little more, but it will save you headaches as well as money in the long run. God Bless