be safe/careful with axle stands, wheel chocks, jacks, crawling under car , etc.
plenty on utube but basically work out if it's LSD or not and then roughly calculate the ratio by comparing wheel rotation to tailshaft rotation
jack both rear wheels off the ground
turn one rear wheel by hand and watch the direction of rotation of the other rear wheel
if both wheels turn the same way (both forward or both backward) then it's an LSD
if one wheel turns the opposite direction (one forward and one backwards or viceversa) then it's not an LSD
if LSD leave both wheels off the ground
turn the rear wheel one revolution and count the number of times that the tailshaft spins
if not LSD then lower one of the rear wheels to the ground
turn the rear wheel two revolutions and count the number of times that the tailshaft spins
e.g. about 3 and 1/4 tailshaft turns ~3.27
(probably 3.27 LSD for 2009 S1 manual VE SV6)