So far I have done the following to my 2014 S Roadster

1.) DDM race intake
2.) Koni Shocks with adjustable damper
3.) AST springs .97" lower
4.) 22mm rear sway bar
5.) Vorshlag comber plates
6.) Hotchkis adjustable rear end links
7.) Miltek Cat-less DP
8.) Akrapovic cat back exhaust
9.) Forge inter cooler
10.) Custom Tune
11.) wilwood 6 piston brakes up front stainless lines all around
12.) M7 front strut bar

Thinking maybe LSD and performance clutch?

 

Powerflex bushings (get the total pack)
adjustable swaybar endlinks
Upgrade your various bulbs to LEDs
F56 style headlight
Add gauges
Sound system upgrade
Replace factory headliner with custom route
Meth injection system
Ultra Racing underbody braces

It's endless really..

 

For sure with all those mods you need the LSD to get the power to the ground. A Quaife is what I would recommend for a street driven car.
https://www.waymotorworks.com/quaife...ferential.html

Then of course upgrading to powerflex bushings while you have it apart.
https://www.waymotorworks.com/powerf...7-r58-r59.html

You can also do the bigger front sway bar with it all
https://www.waymotorworks.com/h-r-fr...ybar-mini.html