not sure about the technical suspension setups, but having installed a cusco front brace on my s2 33 just on the weekend, i can tell you GET ONE!!!
I only have shocks, not coilovers - and ive heard that with coilovers the difference is minimal but shocks is definitely recommended.
the difference is actually amazing. Maybe its just my driving style or the way the car is set up but i find now the steering feels much lighter, and the front grip has increased dramatically. For $150 - 200 for a decent one i would not think twice - my opinion now is that they are quite underrated.
As for working on the engine, it seems they are easy to remove (4 nuts) so personally i wouldn't worry about it too much.
Hope that helps