Do expensive cables/wires REALLY make a difference

After a long journey over the last 35 years I've settled on a complete system of MasterBuilt interconnects, speaker cables, and powercords. Now, anytime I replace any part of the set, even one pair of interconnects, it's easy to hear how the system is compromized. I have the Reference series and they are expensive. There's a no hassle return option. You might want to try the Standard line first and see what you think. If you try them, give them several weeks to break in.

Your dealer is right in that a power conditioner can make a system sound worse, but it's also true that a conditioner can make a dramatic improvement. Which one it is for you depends on how clean/dirty your power is, what components you use, etc. Find a way to try one or two conditioners from the better companies (i.e. Audience, Shunyata, BPC, etc.) and then you'll know. I think most (but certainly not all) people find they make improvements and have some form of condioning in their system, and then there is the added protection from spikes/surges.

I don't think someone can say difinitively whether or not to plug your amp into a conditioner. It depends on several variables, and once you have a conditioner in your system it's free to try it both ways. If plugging into the wall I'd suggest at some point having a dedicated line installed, which you should do anyway (it usually costs less than $500, which in this silly hobby is one of the cheapest upgrades you can make). And yes, a conditioner still makes a difference if you replace the stock power cords. When it comes down to it, in my experience almost everything makes a difference. Whether it's an improvement or not is another story.

Depends on the cable Stealth V10 speaker cables do.

Yes, yes and yes, cables are hughly important. And no, one need not spent a small fortune to potentiate your high end pieces. There are excellent bang for buck products out there that often trump the more expensive offerings. Check out the cable company's lending library and try to bring home as many products as you can. The profit margin is hugh when it comes to cable so never pay retail. It's a mine field out there and everyone has a different opinion.Take your time. On a personal note, I just changed out some of my cables (not for the first time) and my system has gone from mid-fi to hi-fi. Want to buy some cables? Just kidding.

When I played around with interconnect cables a while back, there was an obvious difference between, say the Anti-cables and the Audio Art IC3. The IC3 was more open and detailed.