I found this IIPA recipe that I want to try (http://hopville.com/recipe/14520) but was thinking of changing the LDME to 3lbs and the 60min hop addition to 2oz of the same type. Do you think the balance of the beer will be retained with these changes? Also, what are your thoughts on adding a yeast nutrient?
Should be fine. I've gone as high as 90 IBUs in a beer with a 1.075 og without ill effects, but that might be dependent on the hop variety. If I recall correctly, that was with some cocktail of New Zealand hops.