That back glass is crazy expensive. It's laminated with a tiny defroster grid sandwiched into the middle of two sheets of thin glass. The last one I sold (10 years ago) was over a grand just for the glass. The earlier version of that car had a solid tempered back glass, so you might want to look around for one of those if it really bothers you. The rubber weatherstrip for the glass is probably $200 now, and labor to install will run about the same.
How bad is it?
The Hunter S Thompson of e46f.