Welcome...I don't have an S3, however...if you can snap us a photo of the mounts, I can confirm if they are the same or different.

 

good day,
I am new to lotustalk, but not to the elise, so there's a real good chance i'll not do this all quite right. About a year ago, i smoked the 2zz in my '07 elise/exige (more on why i call it that elsewhere), and decided after some research to change the 2zz to a jdm honda type-r k24a, which btw comes with torson lsd. Also, honda makes the best drivetrains anywhere, imho. Chris, the master acura tech in phoenix, just told me he expects to take the car to the tuner this weekend or monday--it must be tuned on a dyno so 1. i'll be able to tell you its whp; 2. the new hondata computer, which is programmable, can resolve LotusWiring > type-r jdm computer. Fortunately, i'm a retired computer engineer. I'm looking thru my stuff so i can post some pix of the cars. Peace, and i'm confident i'll be back soon.

 

This is what i know about the difference between s2 and s3 mounts: all but 1 (of 4) will fit, but the odd one is on top front i believe (certainly top, where it's available). Chris fabricated a replacement for the odd one, out of Al. The standard s2 mounts don't quite fit, but came very close (3 out of 4, and the 4th lined up fine, but the hole off by ~1cm). However, we used a jdm k20a, which may differ from what you or others use. If i am not mistaken, uses a Rover block, which for some strange reason they purchase from honda, even tho that's the only honda part they use. Indeed, the Rover and honda engines twist in opposite directions. But because lotus s2 uses the honda block, there is but little difference in motor-mount locations. But again, i can only really say that we were fortunate insofar as 3 of the 4 (perhaps branded "Innovative") "conversion kit" mounts we bought worked just fine. I also believe it's fair to say we were lucky.