The book "Lotus Elise - the official story" by Jeremy Walton claims the Sport 160 carries the motor from the MGF Trophy 160 model pre-facelift to TF spec. I'm not entirely sure, however, since unlikely that Trophy 160 owners would have put up with the mega lumpy idle etc...
What I do believe to be true is that the 160 head is the VHPD item, ie big valves, etc, with a set of uprated cams etc and EFI ECU as opposed to MEMS. Not really mappable, IIRC, though maybe that has now changed. Walton also claimed that the ECU was Lotus' own, but I don't think the EFI was Lotus, was it?
The big omission on the 160 was a Close Ratio gearbox...marketing blurb claimed because it made the car more liveable with or some bollox, but somebody else told me that Lotus couldn't afford to include the C/R box in the spec of the car otherwise it wouldn't have sold as price would be pushed too high. Hard to say for sure. But bottom line is...with such a peaky engine, a CR box was surely a must in standard issue?!
I drove Cammy Milne's S160 for a few miles not long after he got it, and loved the suspension (Lotus Sport, though still Konis) however found it really hard to keep it in the "power band"...always felt I was one gear higher than I should have been.
This killed off any amorous intention I had for this particular special edition! The Sport 135 remains the pick of the bunch and it's perhaps no accident that this is the spec I have been inching my own standard car towards since purchase in 1999...the only thing I am unsure of is that CR box, ironically, as it will make m-way cruises just a few dB too annoying for me! What I need is an affordable 6-speed.
It is also no accident that this too is the spec of the car that chassis engineer Dave Minter chose to retain when he left Lotus, the "Ruby Elise" early production car which made at least one Stelvio run in 1999 no less and has over 100k miles on it

And I know he liked it, cos he instructed me when I drove that very car at Knockhill in 99 and mentioned he even preferred it to the Sport 190 they'd brought along for demo laps
Campbell