1) No. If you're talking about wool, it's the weave and the weight that matter and you should probably read the FAQ on super numbers. 2) Polyester is a class of polymers. Terylene is a trade name for a particular synthetic polyester. Why are you considering a poly-blend fabric for an MTM suit? Because it's cheaper? It's silly to go to the expense of MTM and then cheap out on the fabric. Thanks for the answer. Could you kindly point me to the FAQ you mentioned? Also, the 100% wool one is actually a tad bit cheaper. I'm considering the blend because the pattern and fabric appeal to me more. I have to note though that due to my limited budget, neither of them are especially expensive.