tire change
 

Im on RE-11 265/35/19 305/30/19 setup, and I was wondering if it would be okay to keep the front tires (they have 60% thread left), and just change the rears to PSS for the same size.
My original plan was to get a new set of PSS, but unlike the discount tire in Dallas where I used to go, the discount tire in corpus christi is not willing to buy them back.

Has anyone tried different brand of front/rear tire setup?

You'll be fine but fair warning, the PSS's do have a softer sidewall then the RE-11's. Your rear will feel a little sloppy compared to your fronts. Discount tire only buys back tires with 80+% tread life left. ( I lived in Frisco, TX up till 5 months ago and have a lot of friends out there at Discount tires.) Comfort and ride quality will be better but with aggressive driving, your rears will sway a bit more as the RE-11's were built as a streetable track tire and the PSS's were built as trackable luxury street tires.