Sharjah tyre market have all types of tyres and rims, Its after sahara center and before troy university red light. Mostly iranian boys, so bargain it good.
Keep the tire height same and you will be fine. Here is the formula to calculate your present tire height.
Example: 255/65 R17
255 is width, you can increase width to 265 mm or 270mm safely, try not going beyond it.
65 is the 65% of 255 = 165.75mm upper / lower rubber. So for getting total rubber height x 2 = 331.5mm. Then convert to inches = 13.26 inch.
R17 is radius of wheel in inches so to get total height of tire with wheel and rubber add 17 (from R17) + 13.26 (rubber thickness) = 30.26 inch total height.