I have cast after-market wheels from Konig.
A load rating of nearly 1600 is actually greater then the load rating of most tires you'll buy for the car and should be sufficient.
I have drag-raced, closed-track raced and drifted my MM with no issues. I have had to rear after-market rims widened with no issues.
The 40mm offset will work PERFECT for the back (assuming an 8" rim). It WILL move the front wheel outward nearly 1/2 inch. It will be OK, but noticeable and will rub if lowered.
I put a +45 7.5" (same outside lip location as stock) up front and a +40 8" (moving the lip almost 1/2" out) on back and the stance was perfect. I have since widened the rear 2" bringing the offset to +65 on a 10".
Summary, I'd try to go with +50 on 8" up front or +45 on 7.5". +40 on 8" works great out back.
Magindat: (majin-dat) Imagine That.
2013 Ford Taurus SHO
Lemonade - living with Fruit Punch - in Blackmobile's Garage...
FIT Procharger Kit #31 - 3.7 pulley - 9 PSI
World's first BLOW THRU ProCharged Marauder - Reinhart Tuned
#1649
boi