Sonicfox, how far back in the PT catalogue have you gone? The heavy guitar just started on "In Absentia" so you may want to try to find "Lightbulb Sun", and "Stupid Dream". They're both out of print right now so it's rare that you'll find them in stores. I know that they plan to release them under the new record label, but it'll be some time. If you haven't heard PT's live stuff, you should definitely check out "Warszawa" and "Coma Divine" from their website.

I've not heard Dredg before. I'll be sure to check them out though.