The KE30 booster is possible, also the one from a TA22 is possible (I use the TA22 booster). Space for the booster is your enemy. The way my engine bay is setup nothing bigger than a TA22 booster fits (unless I go for a remote setup of course)
Another popular option is the remote booster setup using a VH44 remote booster (a quick google search will bring up more info on this)
Assuming that your brakes are still standard I would recommend an upgrade on these too. A search of these forums should bring up some simple brake upgrades eg KE30 discs and calipers.