I don’t know how detailed @Roadie’s instructions will be, from experience I expect very but just a warning:
Take care when removing the units from the car and don’t be like me. I sent the light unit flying resulting in a chipped lens when removing them 
Follow the manual steps!
Full manual steps for light unit removal:
https://www.mx5manual.com/page.html?docid=SM356245
One quick tip on removing the turn signal assembly housings.
The housing will only pop free if it is moved straight toward the rear. Tilting it or pulling at an angle will just fight the mounting points. The screw and nut are easy to remove but there is a side-oriented clip out at the far end of the housing. Some instructions suggest a pry tool at the lateral pointy part of the housing, or to tap the rather thin bolt from the trunk interior. Instead of using a pry tool which can mar the paint or snap the end of the light unit off or tapping on a bolt which may bend, I suggest you loop something thin behind the point and use it to pull. Fishing line or small zip ties works.
Remember, lots of masking tape, paint around this area is very thin!
I have a non-Roadie exact same version bought and fitted in June 2019 and they have worked perfectly. I paid almost double taking exchange rate/customs costs into consideration, so kudos to Roadie on price!
My install
Comparison (remembering it’s hard to photograph/video LED’S) Effect IRL is better…
Nice tip with the cable ties. Here’s an extract from my instructions -
You can then remove the complete light cluster by pulling towards the rear of the car. I find that gripping the circular part of the lens with one hand with finger tips of the other pulling backwards on the pointed end. Pushing on the rear of the cluster via the grommet hole might help. There is a location clip arrowed in the third picture so don’t try levering the pointed end of the cluster out sideways.
Full instructions are here -
Like you I paid over £90 for mine from the US. Here’s how it works. They are made in China and like most Chinese manufactured parts purchased direct from the supplier are sold at a very fair price. They are then purchased by a retail company in USA, Europe or Japan. That company pays for shipping and duties at the wholesale price. They have premises and wages to pay for and also want to make a profit so add a good chunk onto the price. The customer then comes along and purchases and has to pay another lot of shipping and duties on the retail price.
So when you and I bought ours from the US we ended up paying two sets of international shipping and two lots of duties as well as paying the wages and profits of a retailer.
I haven’t actually been presented with the bill for VAT, import duties and fees yet but have factored that into my price and obviously some profit for me too. Delivered by FedEx who are sods for letting you think you’ve got away without fees and dropping it on you three weeks later! If sales take off and I get into the quantity discounts but that starts at 30 units. This time I went with the minimum 15 which was still a fair outlay. They will even do them with my own branding on the box but that is only available if I purchase 1,000 units. More chance of me winning the lottery and I don’t even buy a ticket!
Received my sequential led indicator kit from Roadie today, great service and great price, looks just like the genuine set.
Thanks Roadie, I’ve just got to fit them know but I have watched the Flyin Miata video on the tube so should be okay, just a bit chilly even in the garage😁
Received my sequential LED rear indicators today and fitted in 30 mins with Roadie’s enclosed instructions. They look soooo much better than the stock bulb flash.
I fitted these to my Mk4 and added a short guide to my blog, including an easy way to remove the light unit WITHOUT damaging the paintwork.
There’s also a video showing the newly fitted lights in action
Adding sequential indicator lights to a Mk4 ND MX-5
Slow but steady sales on these so far. I’m on my third batch of 15 now, sold 32 to date. As long as they keep selling I’ll keep stocking them.
