I think it's time you did a little auditioning.
Find a good dealer who carries some of the products you're pondering. You might first audition an amp upgrade. See if you can take them home and try them in your own setup. This is important because there is no way to tell what kind of improvment a component will make, without inserting that component into your system. Also audition some new CD players and a DAC. A good dealer will let you take some of these things home. You should probably reward that dealer with a purchase, however, as it's not good practice to audition many things, only to later go find something else on the internet. It's all about building a good relationship with a dealer. Plus the dealer has probably heard countless different systems, and can more acurately point out weaknesses in your system. Getting advice from us can only take you so far. Most of us are limited in our experience with different products.
So go out and try some new things, and then you will never question your purchase.
