I wouldnt buy anything from F10 markaz concerning cars, especially Al-Sheikh or anything in the vicinity. They are way over priced, talk really big and try to take advantage of you everyhwere they can.
There is a place near Holidy Inn/Melody called Car Boutique, their prices are reasonable and they dont try to sell you anything you dont want. I'm not sure how big their inventory on things you would want would be though. Also check in Aabpara, as well as getting second opinions on prices and things recommended to you.