I am looking to purchase a pair of pencil condenser mics to record grand and upright piano mainly in a Jazz style. My budget is around $300-$500 per mic. I am interested in the Shure SM81 and KSM137 which I hear are good for piano. Also I am interested in the AKG C451B which is a little more money, but is it worth the extra cost? Let me know your thoughts. Many Thanks