I depends what your trying to achive, but a RRC can be lifted using standard LR springs. My current RRC is on land rover specification green/pink stripes on the front and red/white stripes on the rear and I prefere them to the stiffer HD lift springs on my previous RRC. Being pattern parts the cost quite a bit less that the HD springs, but I've heard that genuine LR springs don't cost much more.
Be aware with dampers and lift kits, some lift kits are supplied with standard length dampers, read the kit discription carefully before spending money. I've run lifted RRCs with standard length dampers quite happily, though you do reduce the articulation slightly.
Longer dampers have their down sides, as do relocating damper mounts (eg lowering turrets). For a start you will likely need longer or re routed brake lines to prevent them being pulled apart when the axle drops or articulates.
Use the search function and you will find a lot of the pitfalls and problems with lift kits have been well discusses before.