This is a great thread!
I was the proud owner of an '81 PE175. I was so impressed with the compact engine and the power, and all that suspension! (I'd been riding early 70's Yamahas) Be sure to LocTite that kickstarter bolt; I spent a miserable day searching for that damn kickstarter.
I bought it for $350, and my parents sold it when I went to bootcamp (in '93). Maybe I'll speak to them again someday.