There is a thread here talking about Ceramic Coatings:
The professionally applied route or the DIY route with many different products to choose from in between.
There are many YouTube videos on the subject too (I watched too many 
).
Not sure of the cost of a professionally applied solution but the Turtle Wax Ceramic Wax Coating 
I bought was £18 off Amazon.
I was always going to apply the coating myself, I am a little bit fanatical when it comes to “washing” my MX5.
What would be interesting to know would be the difference in the level of “protection” offered by the professional solution verses the DIY route. My understanding of the difference so far is longevity of the protection in favour of the professional route.
However, the ease of application of the one I am using means it can be applied after every wash, effectively “layering” the protection
I need to give a further update to the thread above, but suffice to say 4 weeks on, the results are still very positive.