tweaking a brewer's best recipe

Ok, I recently made a Brewer's Best Classic English Pale Ale Kit. Tasted good at bottling. It Seems that all went well. So anyway, I was thinking about tweaking the recipe. The only thing i want to change is the 8oz of cracked grain. All I want to do is change the grain to a darker grain (Chocolate malt). So here is the recipe after tweakage :

5 Gal batch-2 gal boil-60 minute boil

3.3 lbs. Plain light LME
2 lbs. Plain light DME
8oz Chocolate malt (the original recipe called for 8oz Crystal 60)
Steep grains at 160f 20 mins
1oz Kent golding hops 60 mins
1 1/2 oz Glacier hops 5 mins
Nottingham yeast


So anyway, is this a bad idea?
What style would this fall in? What would it taste like?

I'd leave in the Crystal 60L with the 8oz of Chocolate Malt and you will have a brown porter. It will work just fine.