hmm
6" splits for the front work well and mount in stock spots.
i had trouble finding 4"'s for the rear that fit so its still on my to do list.
I used to run SL King springs and shortened KYB shocks and stock swaybars and the ride was pretty firm...
I've swapped out to KW V3's whiteline sways, poly bushes and the ride isn't any harder, it does feel a TAD firmer but it's a more progressive firm so it's no less comfortable... (probably mostly coming from the harder bushes and swaybars meaning the shocks are working straight away and theres no slop. edit: my girlfriend actually says the coilovers are comfier.
i've been runing Kirkasaurus insert engine mounts since about 2005. Initially i ran a solid puck clutch and the car was an absolute monster in traffic or parking etc. there was no give so the car would shudder a LOT and required a lot of revving and prodding of the clutch to maneuvre slowly. My mechanic hated it m"i've driven 1100hp GTR's that aren't as harsh as this" so i figured i'd try a sprung hub for a while and it's settled the car down to pretty much stock but without the slop... no shuddering anymore... HOWEVER I notice the cushioning in the clutch and it took me a while/still not liking the disengagement from power response when in the twisties.... i hit the accellerator and i can FEEL the springs compress and the delay in drive to the wheels.... there were a few times early on where it caught me out badly as i was depending on smooth immediate power delivery mid corner to plant/slide the back end..... for a street car the sprung hub is probably the best option and definately so if its going to see traffic.