This is spice that is moderate by my terms and moderate by eaters of seriously authentic indian food. If you're sensitive to spice...be careful as you add the jalapenos because you might be sensitive to the red chiles.
My way: 6 whole red chiles, soaked in oil, added to recipe but removed before serving. I use 1-3 whole jalapenos or 1-2 jalapenos and a habanero...but I'm brave!
Also works for chicken, beef, lamb etc! I only use about a pound or two of shrimp because I like a heavy sauce.
If you're serving for commercialized indian appetites, you may want to blend the entire sauce. I like to simmer it first, blend it, then add the red chiles and shrimp. You can also drain off half of the sauce after cooking and blend it briefly. Your choice!