I put a new custom string and cables on my Cyclone after only one year.
I shoot alot and the string needed replaced. Wanted to upgrade to custom so I figured I might as well replace the cables as well. I went with ViperX and was more than pleased with the outcome. Two big steps up from stock.
Most of the manufacturers tell us to replace them every two years. I have to replace them much sooner, as I do quite a bit more shooting than any normal user would. I've found that at about 1000-1500 shots most strings and cables are needing replaced. (your results may vary) You will find that you need to replace sooner on the high performance bows.
Good quality strings last much better. Most of the top brands will offer there strings and cables pre-stretched and that makes a huge difference.
Average cost for a premium set of string and cables will be around $90-$110 with a regular set being in the $50 range.
Yes, you will notice a difference in the performance of the bow. It will shoot like new again.(or even better with a premium set of string and cables)
We generally install them at no charge. The Stealth X2 should be very happy wearing a set of Viper X. I would rate them as the best of the premium strings.
Turn around shouldn't be more than two weeks right now,(from your door, to your door) as the season gets closer that will change. Shipping is going to kill it though and you are almost too far away for a drive.