I highly recommend the STS for your bow. Other than reducing the possibility of limb damage from a dry-fire it will also lower noise and shock. Best place is David Wilkins (Wyvern) if you are in the US. Stick with the string that came with the bow(Dacron) for at least 6 months of shooting. Get a couple more and make sure the center serving is black.
You bought a great bow, enjoy!