US Mint Statehood Quarter Proof Sets

Would the silver proof be the ones with the red background on the slab or the blue ?

I just checked the links to the coins you bought and they are the clad variety. Nice coins, no doubt, but if you are looking for a quick buck, you'd best hold off.

The issue prices on these sets were $13.95, 13.95, and 15.95.
I love your enthusiasm, but I did some checking and complete sets (1999-2008) that have actually sold on the Bay during the past 2 months range from $40-75.
I really hate to be be pessimistic, but Red Book values on the sets you already own are $6,6, and 4. The problem with resale of these sets is that they produced about a million of the 5-piece sets plus the regular full mint sets which included the clad quarters and the silver versions of the above. Again, unless you want the your own full set of the 5 piece clad quarters, I'd hold off. But that's just my opinion.

You might get $8 for slabbed PF-70 coins (PCGS or NGC) but for raw unslabbed coins you will be lucky to get $2-$3 each retail. Sell them wholesale to a dealer you might get $1 each. No they aren't a good investment. Look at it this way how good an investment can they be when you are able to buy them years after they were made for 30 to 50% LESS than they originally sold for, and from sellers that probably have access to the same pricing information that you do. That information is easily available and if those coins were really worth $8 each they wouldn't be available for $10 a set.