In the search for the correct seating position I came across this pdf guide which is really good and explains properly how to set up every aspect of your seating position, including the seat, steering wheel, lumbar support, yourself etc.
Definitely worth a read 
https://www.physiomed.co.uk/uploads/guide/file/21/Physiomed_Sitting_Guide_-_Driving_Digital.pdf
Thank you for that link not tried it yet but will when I’m next in the car. The only bit most of us might struggle with in a 5 is the headrest adjustment (fore/aft & up down) I’ll check when I do it as it may already be correct. They’re only about 2 mile from my house too! Not that I need to go there. 
Barrie
After reading this I used to think that my Mk3.5 didn’t have enough room in the cabin despite fitting the Jass performance seat lowering brackets. However now I’m more convinced that the seat is in the right position but the seat itself is at fault. I looked today and you can actually see the profile of the seat bucket under the foam on the base. The leather & foam feel rock hard! I’ve ordered a thin memory foam/gel cushion to experiment with to sit on if that makes any difference.
In the camera flash you can only see one of the squares on the base, but in daylight there’s a matching pair!
Would you recommend the seat lowering brackets?
Are they easy to fit?
Are there any alternative products?
Cheers
The seat lowering brackets do work, although I have mine set slightly up from the bottom because it was almost too low. It depends on your DIY skills but you will need an angle grinder to shorten the seat rails on the bench and it needs a bit of fettling to fit perfectly. If you want to revert to original you’ll need to buy another set of seat rails. My car has the height adjustable seats which when they are on their lowest setting leaves an inch or more gap between the backrest and the seat cushion, I found this a bit uncomfortable. The lowering brackets mean I can bring close that gap up a bit and the seats are more supportive.
Seats are something Mazda have consistently failed to get right on all generations of MX5 in my opinion. I have had lots of VAG cars for my everyday car and every single one I have been able to get comfortable in because it doesn’t matter if it’s a Polo or a Transporter they all have the same seat/pedal/wheel ergonomics. Mazda keep changing between MX5’s the mk1 was a great position but soft seats, early mk2 with two piece seats were pretty good, but they raised the highback seats with the mk2.5 by nearly 1.5" which was bizarre. The mk3 had lower seats than the mk3.5 which they raised by an inch agian for the height adjuster but more overall room. The mk4 for some reason they seemed to nail the steering wheel to the dash and only changed this late 2008 when everyone complained for three years. Mk4 hammock seats may save weight but unless you are a ‘standard’ size frankly they are just weird to sit in.
Come on Mazda, you’re a big manufacturer you ought to be able to get this right then stick to it!
Do the seat rails just unbolt or are there rivets that need drilling out?
I’ve got a 2009 model and the seat is height adjustable. I’m about 5’10" and find the seat slightly too high.
They seem quite pricey @£74 though!
Yes they do just unbolt although you need to remove the ends before you can get to two of hex-head bolts. £74 may sound pricy but if you have a mk4 they the equivalent is $360 plus shipping & taxes!
before
after (don’t worry I did fit the second bolt!)
Looks easy enough, sorry for all the questions!
How do the rails come off the seat? Is it possible to do this without disconnecting the airbag/heated seats connector?
no not possible without disconnecting the airbag connector, there’s two allen headed bolts one is hidden inside the rail just slide it all the way to see it when the seat is out of the car. The airbag/heated seats connector is huge but will come off easily when you get the knack, there’s a black lever on one side squeeze the middle of it to release it’s ‘click’ then pull it back and they will separate.
I disconnected the battery first then waited a few minutes before pushing the brake pedal a couple of times to get rid of any capacitive charge left in the system.
currently got the passenger seat out due to a leak and just wondering what the big black fastener is holding the rail.
Was expecting to see two bolts as per your picture.
Maybe the drivers side is different due to the height adjustment?
Yes driver seats are different I believe, the brackets are listed as different on the Jass website. Interesting Mazda only thought it needed one rivet on the fixed side. Good luck with the leak!
Thanks so much Carl - I’m getting nasty sciatica when driving my manual ND, so this has got to help!
Excellent document. I will certainly use this to reset my seat position the next time I drive. Thanks for the post.
