E60 advice, HELP!!!!!

[chookleng]

Dear all sifu,need your advice and help with my e60. don no how to chose and still unclear about certain question. you see, i plan to change my 4-piece tyres within 1-2weeks time. my question is:1) my current drive tyre is equipped with 16' but thought of changing to 17'. there, i called up a friend in singapore and he had a new set 17' for E60. i was told tat the rich owner get its 16' changed to 18' the moment his car out from factory. as such my friend quoted me for SGD1, 600. IS IT WORTH IT??2) I thought of getting GERMAN make / import tyres. but was told is hard to get german import tyres in JB here. those engineer ask me to get either thailand / japan make Continental / michellin make. question is....WHAT IS THE DIFFERENT BETWEEN "JAPAN vs THAILAND vs GERMAN" MAKE? which 1 better? whilst im looking for the silent / quit tyres while on the road.3) any lobang to intro if wan get the german import tyres from kl? wat r the price? the brand? RFT o normal? PLEASE HELP ME WITH MY DOUBT ALL SIFU OUT THERE. THANKS!!!!!!!!