mcintosh home theater pre-amp tuners.

For the price you paid, you did just fine. The only way you would improve your preamp would be to spend a lot more money on a 2 channel unit. The problem with 2 channel preamps now is a lot of people buy a new one to keep up with the DACs codecs because they also use the preamp as a DAC. If you are just running 2 channel analog with your MX132 the preamp bypasses all the processing circuits. 

You do not have to be an audiophile to appreciate good equipment. The MX132 is a huge upgrade from a Marantz 4300 either the 4300 surround receiver, or the classic quad receiver. The gear you have now is better than 99.99% of the systems people listen to music on these days, think a cell phone and ear buds.