I picked up a set of 15" Holeys with 175/65-15 Continental ContiTouringContact CH95 tires for winter usage. The bathroom scale shows:

15" R81 w/ Conti tires: 28 lb
16" Enkei RPO-1 w/215 Azenis: 38 lb
17" R85 "S-lite" w/ stock Goodyear A/S: 49 lb

I'd seen the individual wheel weights posted elsewhere, but this shows the weight with tires.

 

15" R81 w/ Conti tires: 28 lb= 12 lbs for rim, 16 pounds for tire
16" Enkei RPO-1 w/215 Azenis: 38 lb=15.2 lbs for rim, 22.8 lbs for tire 215/45-16
17" R85 "S-lite" w/ stock Goodyear A/S: 49 lb= 25.1 lbs for rim, 23.9 lbs for tire 205/45-17

I use the R81 for track and autocross and put a 205/50-15 R compound tire on it for low weight and sticky rubber. About 32 pounds.
Each pound lost on the wheels is like loosing 4 pounds off your MINI.

 

It's too bad the R81's are so narrow (5.5")/ They are damn nice looking and lightweight to boot!