6 lbs per corner is nice drop and the new rubber makes all the difference.... very nice setup.... I believe those tires are lighter than the stock 18's which are 25 lbs. The Pilot Sport 4S weight in 19 is 24.8 lbs front and 28.6 lbs rear (a lot heavier than I thought). In the 18 inch size its 23.5 lbs for the Pilot Sport 4S (I remember looking this up before)
Source:
Michelin Pilot Sport 4S Tires
The stock
235/
45R18 Michelin Primacy MXM4 has a diameter of 26.3", a width of 9.3", mounts on a 18" rim and has 790 revolutions per mile. It
weighs 25 lbs, has a max load of 1653 lbs, a maximum air pressure of 50 psi, a tread depth of 8/32" and should be used on a rim width of 7.5-9".