Heads up, measure very carefully.
So I bought new seats in the 90's and the project stalled. Now restarted.
I decided to go with new seats to get some control of the rake (my back does not like the stock rake) and to allow easy access to storage behind the seat. Pluss the originals needed a rebuild. I wanted a comfortable (non race) seat. I carefully measured and the seats fit in the car great but .....
I did not account for some of the details of the Lotus seat design and the cushioning. The Lotus seat uses 2" cushion. Typical practice is 3 to 4" with spring suspension. The Lotus bottom is a recessed pan that effectively puts the bottom cushion on the floor, nearly at the same level of the bottom of the sliders.
So while the seat fits I lost about 2" of vertical and 2" of horizontal seating space. I've taken the springs out of the seat bottom and regained about an inch, I may drive for a while and see if the new foam compresses another inch. If not I'll replace with a thinner piece. This actually feels better, making the seat bucket deeper. For length, I plan to cut into the slanted wall behind the seat (leaving a 1" fiber glass cross beam at floor level) to allow the seat to roll back another inch. I think that will get back to the comfortable situation I had before (I'm 5'8" and 170lb).
Sadly I can not recall the seat vendor.
Ron