I'm awaiting delivery of an '08 MCS. I'm planning on using my 17" R90's as my summer wheels. What can I expect from the new tire pressure monitoring system? Will the idiot light be on all the time?

 

You can install TPMS sensors on the R90s but you need to reset the sensors to work with your MINI. Each location needs to be recognized and if you ever rotate tires you need to reset it. Otherwise if you lack TPMS then your light will come on and stay on. If you have NAV screen on your dash you can reset TPMS yourself- how nice.

If you remove the TPMS from the 08 stock MINI wheels that would work.
Tirerack.com does sell TPMS to add to your older wheels- talk to Alex.
You'd have to dismount the tires from the R90s I think.