Yes got mine there too, also dead easy to fit and the Ford performance download was no bother, just make sure your battery voltage is good and you have a good 'internet' connection speed.
I got mine via Shelby American Inc, during their November sales, they are 19 x 9" on the front and 19 x 9.5" rear. The ET is important to check with what you want the car to look like compared to what you have now.
Like you, I did not want to mess about with bigger tyres.
On the Brake Fluid question, Standard Dot4 Mineral oil should be changed every three years as it absorbs water. Dot5 Silicone Brake fluid does not have this issue, so change to this if your contemplating keeping the car.
As a thought, why not buy a new Trunk Lid with the factory holes already there? Then you don't have to spoil the one fitted. Don't forget to purchase the gas struts for cars with spoilers as they are firmer than the ones now on your car.
Today, I swopped out my three year old Steeda Jacking rails for some nice new Xmas present BMR ones. The BMR seem to have a 'Hammerite' black shiny finish unlike the Steeda which were a spray Black satin.
Also noticed that the BMR Rails,sit flush to the sill seam unlike the Steeda which are...
Its a straight forward job and Ford Performance do a Smooth Black panel which I have on a 2016 car, or a later one with horizontal lines on which came out for the 2018 cars. As they were Ford Official parts, they came with good instructions.
CJ Pony I believe have them available.
I'm over in Stafford, where did you go for your service, would you recommend them? I've BSM here both in Stoke and Stafford and they neither fill me with glad tidings.
That's just a plain weird idea!
The rolling radius will be out ie undersized, and will be over the recommended width for the front rim if your running standard 9".
Carlos Fandango did this sort of thing many years ago, but it's your car at the end the day.