So, after some deliberating, I ordered a set of Corbeau LE-PRO seats (through Elise Shop). These seats look a lot like the ones in the 340R and Exige, but they don't cost Lotus money. They do have holes for a harness and a hole for a 5 or 6 point extension.

Seats looked great when the arrived, nicely packed up.

Together with the seats I ordered the 340R seat frames. I did that, because those seatframes have double shear seatbelt mountings. In future when fitting a harness at least the seat frames are up to the load.

The seats aren't especially light weight (no carbon here). They weight about 6.5kg's each (without the seatframe). The original seat is 7.4kg.

The adjustable driver seatframe is a good chunk of metal and is quite a lot of weight compared to the seat, 3.2kg. The original seatframe is 3.1kg.

Because the seatframes are double shear, you can't use the normal bolts, you need longer ones to fit the seats to the frames. So got a seat of 340R bolts, which are longer.

Initially that seemed to work fine. Put the seat in the car (didn't bolt it in) just to see if there would be any clearance issue's.

And boy, were there problems! The seat reclined much more then the original, and it hit the bottom of the car. Taking the seat out again, we found a number of problems. Largest problems were that the holes in the sides of the seats were way too high. So when attached to the frame they were too low. The passenger seat was so bad that it couldn't be fitted to the frame. Second, the nuts that are embedded in the seat are much further in then Lotus fits them. So at first you think the seats are secured to the frame. But when you remove and reinstall the bolt you see that you're not reaching the nut but only the fibreglass. Wouldn't like to thing about putting the seats into the car like that and having an accident.

Together with some other problems, Yvo Tuk from Elise Shop took the seats back and contacted Corbeau about the problems. It took some time but Yvo persisted and got Corbeau to fix the problems. So a new set of seats arrived! BTW, these aren't just one set, Corbeau has fixed the production process and all seats from now on have the modifications.

The new set looked a lot better. There is still a problem left though. The angle under which the nuts are placed in the seat doesn't seem to be very consistent. Probably not a problem with single shear seatframes, but with the double shear 340R ones you need to get your file out and do some modifications.

Also get some bolts and get them tot a total length of about 56mm. Those will reach the nuts inside the seat and fix them properly to the frame.

When fitting you need to make some adjustments. But to do that you need to take the original seats out first. Use a long extension to get to the bolts and you should be fine for the driver seat.

For the passenger seat you'll need something short. My seats were fitted with the 12.9 allen bolts, so I used my stubby allen key.

It could just fit under the seat :)

So with the seats out you now have loads of room!

You need to transfer the buckle etc. from the original seat to the new ones.

For the driver side seat, you need to see how much rings you need to add to space out the seat. The seats are a bit too narrow for the frame. If you don't use spacers, you will deform the frame and on the driver side the seat won't slide.
With my set of seats we ended up using 3 rings on the left.

And one ring on the right. Put it in the car and see if it slides. Don't forget to test it with yourself in the seat. in it.

Now for the passenger side there is the same spacing problem. However, you need to make sure you space the chair out to the center of the car as much as possible. The seat is very near the seatbelt. So on the left side of that seat gets no spacers. And, you need a 340R bolt in there. The seat gets very close to the center console, so you need something flat. Without spacers the bot just reached the nut.

On the other side you need a whole stack of spacers to make sure you don't deform the frame.

At this side a new bolt will fit.

And you also need to space out the upper bolt.

When you get the seat int he car you will see the problem with the seatbelt.

We did two thins to solve this problem, first remve the pastic cap from the seatbelt guide. Second, run the seatbelt through the seat.

That was the last of the problems. The seats now fit and work really well with the standard seatbelts. With everything in place a good set of harnesses needs to be next.

Update 2010/09/14

After having used the car for over 7000km with the new seats (including track) I'm pretty happy with them. They are quite comfortable, but you do need to remove the standard seat cushion as it is too thick. One disadvantage of the seats is that they are a bit more reclined. This makes it virtually impossible to get the roof behind the seats. Have to see if I can find a solution for that.