Tire pressures with 18" wheels
 

I just picked up my new JCW last Friday. I checked the pressure Saturday morning and the fronts were 3 lbs down.I pumped the fronts to 42lbs. I am thiking that I liked the tires at 39 all four instead 42f,39r. I am I in jeopardy of doing any damage or premature wear doing this?

What I found is that my car rides notably better (less harsh/bumpy) with the tires at 37 vs 40 (which I think is recommended on the door sticker). I doubt it makes any difference in anything else.

Lower tire pressures
 

I lowered the cold pressures to 40f, 38r and it seemed to slightly numb the on-center feel, which I like. I like quick steering, but not twitchy. My last car was a Cayman and it's steering was a little slower. Overall, I really like my JCW's handling, just trying to dial it to my taste. Thanks for your replies.

so long as the sidewall isnt laying over on turns..or saggy when parked, your running enough air pressure. Im on stock still and run 30psi all around.

*btw- going off the sticker on the door is as useful as asking Mini when you should change your oil! Those are recommended psi based on the load capacity of the car..and have no bearing on daily driving without passengers/cargo and crap runflats.