cables are they worth it?

As with anything else, if YOU can't hear the difference it's a waste of money. If everyone around you persists in raving about the Emperor's new clothes, that's no reason for you to pretend that he ain't naked. Listen carefully, rely on YOUR perception, and make an intelligent value judgment.

"Cables are they worth it?"
Yes - keep the Cardas. A really great inexpensive interconnect for around $130 is the Cardas Twinlink.
I'm using all Golden Cross, which is my favorite, all bought here used on the 'gon.
My advice - Keep all your equipment but ditch the pre and power amp and save up for some really good amps.

Thank you for all the advise, I think I will hang on to my Cardas interlinks for and save for a nice amp (2nd hand). I know this this the wrong thread but do any of you have experience with Symponic Line amps? Also thinking about buying a tube or SS pre amp and keep the Rotel power amp (RB-1070) for now. There are so many options that for me it is sometimes difficult to see what would be the best option.

All other advise it welcome, I have been in the audio hobby for about 5 to 7 years now and there must be lost of people out there who have a lot more experience then I have. feel free to mail me if you want.

In short, no - an $800 interconnect is ridiculous. Likewise for a $50 power cord. I am sure someone would sell an $800 doorstop also - because it will "just hold the door open better". THere is one huge advantage to expensive cable and power cords - it allows for large profits. Good old Belden cable or any other reputable big name manufacturer will work just fine. You can terminate your own interconnects for that matter. Look at the cables used in other areas of electronics that either deal with low level signals or feed power to critical equipment. The power cords on ventilators are nothing special and they keep people alive. The interconnects on biomedical research and clinical equipment are also not particularly special - I worked in that field for decades (background is EE). What you are sending between your preamp, amp, source etc is just information - it isn't even in a form that is all that difficult to deal with - it's rather high level (certainly not in the microvolt range) the frequency range is not difficult to deal with, you don't have dc offset problems. Don't you think that information that determined patient treatment would use $800 interconnecting cables and expensive power cords if there was a reason to. (Some manuf did use lo leakage pwr cords for electrosurgical units - but I doubt that you are going to use your amp for any surgery in an OR)If you are worried about induced noise, what is important is whether you have a balanced connection or alternatively, a properly grounded or common driven shield as the case may be. That doesn't add any significant cost. As to a power cord - there is just no reason to not use any power cord of the correct wire size. A much more important area to consider is providing a good ground for your equipment.

the amp (....) is a Symphonic Line RG9 mkIII

Right. I once had a RG 10. The spkr cable I then chose was Nordost (the bluish-purple one). And single-core unshielded for my sources -- EXCEPT the TT of course.