Questions from Hong Kong

[eryck]

Hello all. I am a newbie in Hong Kong. Just got my X5 on Saturday. Space grey, 3.0si. I debated for a long time over 4.8 vs 3.0 but decided on the 3.0 because in Hong Kong, all options are the same. The cars here come fully loaded (glass roof, leather, sports steering wheel etc.) and the only difference between a 4.8 and 3.0 is the engine size and price - USD32,000. Yes, the 3.0 costs USD90,000 here. Second reason is that it's for my wife and baby's use....but I still want it to look good so here's my question:

I would like to put the 124 Y-spoke 20" wheels on. Was quoted USD1,400 for after market ones (but look exactly like OEM - was told that they are made in Italy) and USD3,100 for OEM wheels. Tires are USD1,666 for Yokohama ADVAN-ST 275 front and 315 rear.

First question: is there a big difference in terms of safety between OEM and aftermarket? (After discussing with my wife, I think I'll go for OEM but just wanted to check with you all)

Second question: If I get the 20" wheels (mine's 18") without changing the suspension e.g. sports package, will it screw up my existing suspension system? (I know the ride will be harsher).

Last question: does anyone know if we can buy the 4.8 exhaust tips? Mine comes with the round polish tips but I prefer the 4.8's oval tips.

Thank you in advance for any advice you may care to share.

PS - By the way, I also order the aero kit. Cost me USD1,400 without paint or installation. Seems like everything is expensive here in Hong Kong.