^30bhp extra doesn't equate to 1.2 seconds quicker.
I admit to not reading the advert fully, but presumed the car is a stock PPP, not re mapped.
Copied from zero to sixty website, I've bolded the fastest and slowest C63. There is 0.7 seconds difference between fastest and slowest.
MERCEDES 0-60 TIMES
MERCEDES C63 0 TO 60 MPH AND QUARTER MILE TIMES
2011 Mercedes C63 AMGCompare0-60 mph 4.3
2008 Mercedes C63 AMGCompare0-60 mph 4.0 | Quarter mile 12.4
2011 Mercedes C63 AMG DR520 EditionCompare0-60 mph 4.0
2011 Mercedes C63 AMG P31 Development PackageCompare0-60 mph 3.9 | Quarter mile 12.2
2015 Mercedes AMG C63 SCompare0-60 mph 3.9 | Quarter mile 12.2
2017 Mercedes AMG C63 S ConvertibleCompare0-60 mph 3.9 | Quarter mile 12.2
2017 Mercedes AMG C63 S CoupeCompare0-60 mph 3.8 | Quarter mile 12.0
2014 Mercedes C63 AMG Edition 507 CoupeCompare0-60 mph 3.8 | Quarter mile 12.2
2012 Mercedes C63 AMG CoupeCompare0-60 mph 3.7 | Quarter mile 12.1
2017 Mercedes AMG C63 SCompare0-60 mph 3.7 | Quarter mile 11.9
2012 Mercedes C63 AMG Black Series CoupeCompare0-60 mph 3.7 | Quarter mile 12.1
2013 Mercedes C63 AMG Black Series CoupeCompare0-60 mph 3.6
2015 Brabus Mercedes C63 800 Bullit CoupeCompare0-60 mph 3.6
2019 Mercedes AMG C63 R0-60 To Be Released
Edit.......read the advert and the seller is implying a bog standard C63 does 0-60 in 5.6 seconds!
He is so wrong.
Its sold anyway.