Whole Wheat Sweet Potato Muffin Recipe

Oh my goooooooooooodness!!!!!! I adapted the pumpkin carrot muffin recipe I've been using to make some sweet potato muffins and I was blown away! I like them better than the pumpkin carrot muffins! Here's what I did:

Mix
1 1/2 cups mashed sweet potato
2/3 cup brown sugar
1/4 cup oil
2 large eggs

Mix
1 1/2 cups whole wheat flour
1/2 tsp salt
1 tsp cinnamon (I also threw in some Capella Flavor drops [cinnamon, about 24 drops] and some pumpkin pie spice, probably 1/2 tsp)
1 tsp baking soda
2 tsp baking powder

Stir the sweet potato mixture into the flour mixture until moistened. Spoon into 12 muffin cups. Bake at 375 degrees for approximately 20 minutes.

Per muffin:
180 calories
6 g fat
30 g carbs (2.5 g fiber)
3.5 g protein

I would love to find a way to cut some carbs and boost the protein a bit. Is brown sugar necessary or can I use Splenda? I know there's a brown Splenda, but I like the liquid Splenda.