I thought I should update his post, just in case anybody is interested. Then I have more questions. Always more questions. They relate to mounting seats to the floor so for anyone totally disinterested in Rev Plus seats, please skip most of this essay I call a post.
One of my 2012 Sparco Revs ('grp-tech' on the backrest, not 'rev plus') arrived today. It's a very very small seat. I'm a 28" waist and it is very nearly snug. I would recommend this seat only for slim drivers - average size (32"+) will probably be either tight or too tight. They are very comfortable although I can't give feedback on long-distance endurance yet.
As far as space, my initial worry was that the wings would be too wide or the base would interfere with the transmission tunnel. Again, it is a tiny slip of a seat and there is actually more space either side of the seat than stock. The outside wing hits the door trim and squeaks constantly, although that is almost certainly a mounting issue.
Mounting was harder than it could (read: should) have been for reasons covered below. I bought the regular sparco side mounts (in red, because red goes faster - seats are in black though). My initial intention was to mount the brackets to the floor, using spreader plates with nuts spot welded on. This seems to be accepted and safe. Sitting lower was always the plan, for more headroom (the softtop frame is frightening), better weight distribution and to clear a planned roll-cage. Adjustibility would be achieved by the 5 different holes offered on the base of the mount. Sure, not a 30-second job any more but it'd do in a pinch. It still is the plan but as of this moment, the seat is mounted, after two hours of back and forth with small bolts and metal plates and and angle grinder to the (stock!) rails. Honestly, it's not all that confidence inspiring, and I wouldn't invite anyone to come and try it out in a hard corner or, worst case, an accident. The best part is, in return for slightly iffy safety, the seat sits higher than stock (my head now hits the roof, and I'm 5'11" with average leg-length), whch to me is no surprise, but leads to my questions.
Now for the questions:
1) As far as i have read, the rear mounting points for the stock seats are spot welded down and can be drilled out and removed. Is there any danger in doing this, and what is beneath those lumps? I presume it is the floorpan but would rather not find out otherwise the irreversibly hard way, and;
2) The front mounting point appears to be a rather thin piece of honeycombed steel, the purpose of which is to provide somewhere for the seat rail screws to go rather than through the floor. I can see the floor beneath it so i know it's removable but: dad (no experience with mx5s beyond mine, but has built his own track car. From the 70s so made from steel girders) thinks that it's a crossmember although it makes little sense to me - it's neither particularly solid, nor would it seem to be placed to resist any particular stresses the car would experience short of a side-on collision. I've also seen track cars without this (also for seat mounting purposes) and that alone suggests it's not so vital. Is this piece structural, and, if it is, can it's removal be justified in terms of achieving proper seat mounting, and rectified (if necessary) by adding similar cross-cabin bracing that doesn't interfere with my seats?
Yes it means that I can't just replace the stock seats if i want to sell but my mx is so old and with so many kms i doubt it'll ever be sold on as anything other than a fully rebuilt track car (also, i love the thing).
Cheers (if you made it this far, apologies for the thesis
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Stu
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