Viva Glam V is my absolute favorite lipstick. It's such a different finish from a slimshine that since you've already spent the money, I'd recommend keeping it. I wear VGV when I don't want shiny lips, I think it's great to wear with a more intense eye when you don't want your lips competing for attention.
I also have found that slimshines get used up pretty quickly, so you'll probably be wanting to replace the color in no time - and now you won't need to, since you'll have VGV.