The tax exemption is an IRS process so that will be the same regardless. I think you would have to hire Delaware counsel for a Delaware incorporation, you'd still be subject to the attorney general registration and tax filing requirements and Delaware counsel is probably going to tell you to hire Massachusetts counsel anyway because there are a lot of state specific considerations and you'd be doing business in Massachusetts so you'd also still need to file annually with the secretary of state as a foreign corp and maintain good standing in Delaware with whatevers required there.