Great cars, love mine.
I wouldnt mod the suspension personally. Maybe some RS-R -20mm springs and chop the bump stops slightly and add a RS-R tie bar too, but no way I'd enjoy coilovers knowing how stiff it is already. I would put it on par with Tein supersports on full already.
So must ruin some of the fun you can have with the coils on. On the the road anyway.
I have a Monster filter and OMP braces too, but only modded the intake route not cut the box, as it looks less than ideal for sitting in traffic.
People make me laugh when they think they dont get from A-B swiftly enough, they really do get up and go from rolling to 80-90mph, and stop and turn in great.