I like large wastegates. The larger the better I always say. Unless you have packaging problems with that large of pipe, I would keep it and use it.
I know the argument against using a larger than needed wastegate, but I think the down-side is blown way out of proportion.
I'd rock a 50mm wastegate even if I didn't plan on making much power at all. Hell, if I could fit it and afford it, I'd do 60mm.
But I'm crazy like that.