Tires: Tires- replacing 2 or all, general grabber uhp, continental contact

Question
I have 2 worn rear tires that need replacing.  The 2 fronts are still OK but will need replacing with a little more wear.  Originally, i was planning on finding the 2 cheapest decent tires with the same size to replace the rears, and worrying about replacing the 2 fronts when they were worn in the future.  That will probably not work out though because I was advised by the tire replacement place to stick with the same make and model if i was only replacing 2, but the tires i currently have on my car are fairly expensive although i am not a big fan of them (continental contact 4X4 275/45/r20 110h xl).  Now i am thinking about instead getting 4 brand new  general grabber uhp's (with a 110V rating) because they are well rated and are significantly cheaper- so much so that it would only be $100 more to get 4 new tires instead of the 2 new continental's.  Do you think this the right move?  Any other approaches i haven't thought of would also be appreciated.  Thanks so much in advance.
-ilya

Answer
Ilya,

It is not clear, but it sounds like you may have an All Wheel Drive or a 4X4.  If so, then it is more than recommended that you alway change tires in sets of 4 in order to prevent drive train problems.

If not, then it's a little unclear why you are going through all these gyrations.  Perhaps a bit more from you might help me understand. (unless, of course it is the first one!)