I'm currently running a 18inch wheel with 225/40 rubber and adjustable suspension but I don't like the adjustable suspension as I feel bumpy. I'm planning to run koni suspension with eibach spring will this set up will rub the fenders if so any other suggestion. Thanks

Yes check to make sure the bump stops have been cut down first as the shock could be bottoming out making it feel bumpy.

Will check on that..... Is it must have adjustable absorber to use 18 inch wheel?

You can run standard shocks and springs with 18" rims, it's personal preference.

There is no physical reason why standard shocks can't be fitted, but 18" wheels will normally be quite a bit heavier than standard, so an uprated shock absorber may be required to control wheel movement

Can I use koni suspension with lowered eibach spring?

Running on 18" will be always rough ride compared to stock, and the Koni shock are hard even in their softest setting. Bought my second Coop with similar set-up and changed it back to stock wheels and shocks because for everyday/city usage was very annoying, left only the lowering springs. It isn't the perfect solution, but much more acceptable.

Which adjustable suspension are you currently using?

I would avoid koni's as they are sleeved through the housing of the stock dampers which eventually comes loose and starts knocking.

I'm using a malaysia local brand suspension name titan

When were the Titan's last serviced? Did you have them from new? If set up right, it shouldn't be too bumpy...unless they are due to be serviced. From my experience, the bumpy feeling comes when the dampers have loss its gas pressure..in which case, Titan would be able to rebuild them for you for not that much. You could even ask them to alter your settings to a more comfortable one if you so wish to.

I just service the suspension today will update how is the set up soon....