Other options...
Tire ratings, TireRack, sorted by noise from worst to best, selected tires:
6.4 Michelin Pilot HX MXM4
http://www.tirerack.com/tires/tires...l=Pilot+HX+MXM4
Dry Traction: 7.1
Wet Traction: 5.8
Hydro Resistance: 5.8
Snow Traction: 4.4
Cornering Stability: 6.4
Steering Response: 6.7
Ride Comfort: 6.7
Noise Comfort: 6.4
Tread Wear: 6.2
6.7 BFG KDWs:
http://www.tirerack.com/tires/tires...Force+T/A+KDW
Dry Traction: 9.0
Wet Traction: 8.2
Hydro Resistance: 7.9
Cornering Stability: 8.8
Steering Response: 8.8
Ride Comfort: 7.2
Noise Comfort: 6.7
Tread Wear: 6.9
6.9 ContiTouringContact CH95:
http://www.tirerack.com/tires/tires...ingContact+CH95
(300C RWD OEM tire)
Dry Traction: 7.6
Wet Traction: 6.8
Hydro Resistance: 6.8
Snow Traction: 5.8
Cornering Stability: 7.0
Steering Response: 7.1
Ride Comfort: 7.3
Noise Comfort: 6.9
Tread Wear: 6.0
7.1 Goodyear Eagle F1 Supercar
http://www.tirerack.com/tires/tires...gle+F1+Supercar
Dry Traction: 9.4
Wet Traction: 6.0
Hydro Resistance: 4.8
Cornering Stability: 9.3
Steering Response: 9.2
Ride Comfort: 7.7
Noise Comfort: 7.1
Tread Wear: 6.4
8.5 Goodyear Eagle F1 GS-D3
http://www.tirerack.com/tires/tires...=Eagle+F1+GS-D3
Best match for 300C: 255/45 YR18, 103Y XL, $193
Dry Traction: 9.2
Wet Traction: 9.1
Hydro Resistance: 9.0
Cornering Stability: 8.9
Steering Response: 8.8
Ride Comfort: 8.6
Noise Comfort: 8.5
Tread Wear: 8.0
8.7 Goodyear Assurance TripleTred
http://www.tirerack.com/tires/tires...ance+TripleTred
(Not yet available in sizes larger than 17")
Dry Traction: 9.4
Wet Traction: 9.4
Hydro Resistance: 9.4
Snow Traction: 9.1
Cornering Stability: 9.0
Steering Response: 9.1
Ride Comfort: 8.8
Noise Comfort: 8.7
Tread Wear: 9.2
9.3 Goodyear Assurance ComforTred
http://www.tirerack.com/tires/tires...ance+ComforTred
Dry Traction: 9.0
Wet Traction: 8.7
Hydro Resistance: 8.7
Snow Traction: 7.9
Cornering Stability: 8.2
Steering Response: 8.0
Ride Comfort: 9.2
Noise Comfort: 9.3
Tread Wear: 9.0
Note what an absolutely awesome tire the Goodyear Assurance TripleTred is--magnificent! But it's only offered in 16" & 17" sizes so far.
This is quoted from an earlier post. Thought it relevant.