I've made these Coopers kits up with 100% extract, 75% extract and 50% extract.
I find 100% extract doesn't give the right mouthfeel for a lager. To be honest, there's not enough difference between 50 and 75% to justify the extra cost, so being a cheapskate, 50% gets my vote.
...any more extract is a bonus, and highly recommended if you're going for a stronger brew.
