Definitely don't. A lot of the tiles can simply be replaced via a direct import, (I believe the palettes have been preserved.) and I left a lot of background-transparent tiles available for overlapping onto the new grass styles. Shouldn't be too much of an issue.
Although, to be honest, no combo work should be done between the two sets. Import graphics only, as only a replacement of what is already there and parallel between the two. We should mess up as little as possible in any transitions.
