oh yeah, there's gotta be new blood, i keep getting tags and d2.0's,i'm up to75 D2.0's and platinum knife! i was 5 away from platinum and got 10 in one game, including 3 from the same guy in the same spot.
it's always been 2 C4's to take out a tank. 1 mine *can* take out a tank sometimes if it's directly over it, but it's not reliable, i know i've been in a tank many times and seen a mine too late and hit the brakes and ate 70% damage, and i've also been a passenger and seen a mien and troed to spot/shoot it and then bailed because i can'ttell the driver, and they drive right over it and usually die.
the website that image is from goes into a little more detail on damage vs armor
http://denkirson.xanga.com/722757523/bad-company-2/