Careful positioning of your speakers will have a considerable affect on the overall level of performance of your whole system, so it is worth taking the time to get it right. Firstly, if your room is rectangular, you will normally find that you get a better sound with your speakers positioned along one of the longer sides of the room. Normally they should be placed so that they form an equilateral triangle with you, when seated in your usual listening position, making the third corner. Both speakers should be the same distance from the wall behind them. The spikes must be carefully adjusted to ensure the speakers are level and rigid.
Cables Always use good speaker cables and interconnects.
Again your dealer will be pleased to advise you but it is also worth borrowing a selection of cables from your dealer, where this is possible, to try out for yourself.