Why don't you visit an audio store to see if what they have to offer better suits you? It's free for you to visit the store, explain your situation, listen to a few demo systems and LET YOUR EARS determine whether or not your current system is where you want to be.
Certainly, there are many that are very happy with their McIntosh systems similar to yours. Mac has a good reputation and even better re-sale. If you bought yours at Garage sales, you're really coming out ahead. Withstanding, there are many other manufacturers out there that are known for their exceptional sounding gear. To make assumptions that spending more money and "winding up dissatisfied and annoyed with the cash spent" is ludicrous. Pretentious or not, many have made the move up from their Mac gear, myself included in the lot, and haven't looked back. Before buying power conditioners and cables you owe it to yourself to see and hear what else is available. Determined by your finances, you may not be able to replace your Mac gear with better sounding gear. Then again, maybe you will. It is your choice, your hearing, your money. Listen to what else is available first.
As a side note, you haven't got much help on this because of the way you worded your "subject" field in your thread. HI FI PRETENTIONS sounds more like you are upset that anyone dare say that Mac isn't the best and that anyone saying anything else is just being pretentious. Once again, it's ludicrous. You scared many off from giving you useful advice because of your "Hi Fi Pretentions" title. One can assume that you are 1) looking for an argument or 2) only seeking advice from those who will agree that you should keep your Mac gear.
