I had SC3's on the MV6 for a while, replacing a set of SC2's. I preferred the SC2's to SC3's due to, IMHO, better grip. Think I got about 12k from them, but was probably 3 or 4 years ago - certainly had the SC3's on, and at end of their life at one of the Burns Farm Lakes meets.
Went back to my old favourite SP9000's after the SC3's, due to better grip. I tended to get 15k from SP9000's before the tramlining became too much at around 3mm.
MV6 currently on Sport Maxx, a tyre I really like. Fantastic grip, brilliant precision, nice feedback in the corners and under braking. Sadly, durability doesn't look to be great, I reckon I'm on for a sub 10k 
What would I buy tomorrow? If I was rich, I wouln't own an Omega it would be the Sport Maxx. Back to reality, I'd like to have a gamble on KU31s, based on them on the Rover, and the fact Kevin Wood is haapy, and he's not afraid to sling it into roundabouts without wearing out valuable brake pads 
All the above is based on 235/45/17 though, no experience of 245/40/18 yet
If you can find any ..
Rare as rocking horse poo
All suppliers I've tried say they are superceded by KU39's ... and noone sems to have fitted these to report how they behave on an Omega 
Reason for the thread is sc3 in my current size is...
http://www.camskill.co.uk/m61b1066s4774p61193/CONTINENTAL_TYRES_CAR_CONTINENTAL_SPORT_CONTACT_3_CONTISPORTCONTACT_3_-_245_40R18_93Y_(MO)_FR_TL_Mercedes/RS_GB£152 best price I can find .
Might do better locally, but fair to say that's an expensive set of tyres.

I could stomach the price, i think, if they lasted a little longer.... As you'll recall, I don't know how many miles they have done, but I suspect no more than 11k...

So, here we find ourselves, all in a similar boat.
What to fit next...? :-/