Since all support and service in that part of the world is handled through independent dealers, it is very risky to buy through non-authorized channels. You can find yourself without warranty coverage at worst, or having to ship the system internationally for repair should it be needed.   Be careful with low-cost suppliers -- the up front savings can rapidly become a false economy if service is needed.  
On Dell US sites it is less expensive then in UAE. Is there any other purchasing option for UAE?
Alienware m18, where to buy in UAE?