Discovery lift with air and ACE ??

Hi folks, can anyone advise whether lifting my 1999 TD5 Discovery with air and ACE would present any problems?
Is it essential to alter brake lines at the same time or is their enough free slack?
Other than air suspension bag spacers, front springs and front /rear shocks - what else do I need to buy? Is there anything else which needs to be altered / extended?. I am looking to keep the air ride system as it has not given any problems thus far (touch wood).

Thanks,Will .