a77med

The stock 2009 in here comes with 18s compared to the 20s in the US and on "some" 2010s. I kinda like the looks of the 20s but a bit worried about the stiffer ride and possible effect on off-road (sand) performance.

I've got mine 2 months ago. The ride on the 18s is almost fantastic on the "neutral" suspension setting for city driving but not quite to my taste on Sport mode for highway driving. A tad of sportiness would almost perfect it for my taste.

I am mostly doing city driving and the roads, not the highways, here are a bit far from perfect. How smooth/stiff would the car be on 20s compared to the 18s?

If it helps to relate, my other/older car is a 2003 Accord V6 which I absolutely loved...!!!!

03LX470

Are you in the GCC? I am in the UAE. I believe mine was the first GCC LX570 with 20" wheels (purchased in May 2008). I had the original LX570 chrome wheels with tyres shipped to me from the US just in time for delivery of the LX. It cost me a fortune with the air shipping but it was worth it as the local dealers here didnt even offer the 20" option.

As for the ride, if you havent driven with the 18", you will not feel any difference. If you have, you will feel a slight difference. The LX570 is very powerful so going up in size will not harm you as far as acceleration is concerned.

The main thing most customers worry about in the UAE with regards to increasing wheel size the diminished ability to drive in the desert. If thats a consideration, you're definitely better off with 18". However, you will not be at a very big disadvantage with the 20" simply because the you still have 50 profile (285/50 R 20 if i remember correctly). Thats still a lot of rubber that can be deflated for those Big Red, Faya or Pink Rock drives (you will be familiar with these places if you're in the UAE).

In short, if you will have a lot of desert use, better to stick with 18". If not, go for 20"

Hope this is helpful.