could somebody help me out on the benefits of expensive phono and speaker cables?

Here's some info to  sink your teeth into. Plenty of useful info from someone who does know what they are talking about.

http://www.roger-russell.com/wire/wire.htm#conditioner

You may already know the author is a known designer. At least you will have more perspective on your decision. 

Playing with audio, and navigating thru forums IS MADNESS!