Tirerack certainly likes the Conti as an Ultra High Performance tire. Like you, I am on a lease and am pulling my RFs for lease end. I carefully considered the Extreme Contact DWS (I assume this is the tire you are considering - you only mention Conti DWS). I decided to go Highway All Season instead because the softer compound of high Performance tires (faster wear - especially on less than smooth roads). Here in AZ, temps get pretty high and the highways are having serious chipping/flaking probs.

Based on Tirerack reviews, I am going with the General Grabber HTS. General Grabber HTS (click on the tests tab to and then Read Full Test Report (next to video). Nice warranty and strong reviews: Consumer Survey Results By Category

I have a 30i with 18s so i don't know the 20s specs. This tire comes (according to tirerack's size chart):

$147.00 (ea.) 275/45R20 110S
$145.00 (ea.) 275/55R20 117S
$153.00 (ea.) 275/60R20 119S
$157.00 (ea.) 275/60R20 119S
$191.00 (ea.) 275/65R20 126/123S

Don't know if you want to consider this or not but thought I'd offer it as you are asking. Both are great tires, several here have posted getting the DWS and seem very happy. Mine should be here tomorrow and installed on Wednesday.

Best wishes. Let us know what you decide and how you like them once on your X.