just drive the car now, easiest way to tell, if your not sure what car with and without lsd feels like at all get someone who does to drive it for you, easiest way by far
^^^^^^
Agree with the above, only ek9's came with s4c LSD
If you can't tell then best way to check is take driver side shaft out an have a look thru the shaft hole
And EK4 SiR's although it's just a viscous type in comparison to the R's helical version.
Not all s4c boxes are LSD my Jordan comes with a s4c from standard and that is non LSD
Think you'll find sir optional diff is helical also
Is it right enough? I have a facelift sir with LSD and presumed it just a viscous like the del sol's and eg SiR's.