Are you happy with the adjustability of the koni/fc setup? the rates good for you still? Are they low enough for your driving style?
If yes, then rebuild the koni's...do you have access to another car for the down time? Buying a cheap suspension seems like a hassle to spend money and swap that on/off while waiting on the koni's and then have to sell off the other suspension once you get the koni's back.
If for any reason you want to go with a different coilover setup or arent happy with the koni/fc, now would be a great time to do that. Sell of the koni/fc setup and let someone else pay for the rebuild.