Yeah, it's not all that uncommon, actually... "John" brings in his 20-year old motor for service work. While the mechanic is working on it, trying to get seized up bolts or such off, something breaks. Now, John wants the shop to replace that broken part for no charge. You can see how this can get tricky for a business. Granted, if business was extremely slow, which it is not, they may become more lax on their policy. But right now, they have to do what's best for the business - and taking care of existing customers has to come first, along with those that boat the boat from them.
Remove your injectors and send them/take them to an injection shop. 'Bout $20/per.
Also... you might have more luck if you go in and buy some things from them, first. An anonymous email doesn't mean much. Buying things in person shows them you want to become their customer. In the three years since you've had your Grady, you've never once set foot in the service or parts department to buy some supplies?
By the way... what's wrong with a Sea Ray? They make an awful nice boat. Besides, did they even offer OB-powered boats in the mid-80's?