I can't see why a lift will affect the gearing. Larger tyres would, but a shackle lift won't have any gearing effect at all.
It will affect handling though. The caster will change meaning the self centring of the steering will be different. Also the 'weight' of the steering will change. And because you are raising the centre of gravity, it will change the roll characteristics.
Longer shackles also move the springs laterally more, so the car will feel like it's wandering across the road a little more.