Hi Daren and welcome
I would like to know what you didn’t like about the Mustang and why you switched as I have always wanted a 5.0… no need to mention fuel costs though as a reason! 🤣
One of the best and cheapest upgrade is the valve delete plug you can buy on here followed by lowering springs.. after extensive research I went for these below that were made specifically for the RS and unlike others great on UK roads as softer, plus drop more to rear and get rid of the ass up US look improving the looks ten fold… then you have induction kits and a 380 remap… 400 and over and you are looking at forged engine parts… if you hate the high seat position as I did that can be solved too with a JCR kit, again can be bought here. Then you have exhausts (love the borla for the grunt n burble) and more, list can go on and on..
My advice through is enjoy getting used to the car for a few months and driving it as stock as it’s great and then you will really feel/see benefits when you upgrade, have fun and link for springs below / Enjoy and sure others will suggest lots more!
Al 😬👍🏻
https://pumaspeed.co.uk/product-Focus-RS-Mk3-Pumaspeed-Eibach-Special-Edition-Lowering-Springs_17103.jsp
Eibach Pumaspeed springs UK – Mountune full Induction – delete valve plug – carbon knob – JCR seat lowering kit set @ 39mm – black nuts! Engine forged by FJRS – TCR front splitter V2 and side skirts – RS rallyflapz – Car serviced/maintained by GS Motorsport