One thing you asked a few posts back was about changing the sulfate for a beer like an IPA. The answer is "yes, but....."
What I mean is this- some water profiles have you adding up to 300 ppm of sulfate for IPAs and other hoppy beers. In my experience, I prefer IPAs with much less sulfate, more like 50 to 100 ppm.
One thing that these water gurus suggested was make the IPA with less additions the first time. Then add a little gypsum to the glass, to see if you prefer it. Some do- I think mabrungard prefers more sulfate- and some don't (like me). The best answer is "try it and see". If you go low on additions the first time, the beer will still be great. It may not have the hops "pop" so much, but it will still be great.
I made an IPA today with mostly RO water (all RO for the sparge water), and used 5 grams of gypsum and 3 grams of calcium chloride, for 15 gallons of brewing water (a 10 gallon batch). That's pretty minimal, but it's how I like my IPA!