I believe with the BOSS units, the warranty is void if their lines are not purchased, so in my opinion, it's not an optional thing but a requirement to purchase, and I think for $235 they're kind of hosing you (pun intended)
Turbonetics offers a 1yr replacement no questions asked, SP is very flexible in their warranty as well from what I've read.
I'm still undecided what to do, my car is in the shop getting worked on (car audio) then it has an apppointment with the air conditioning people, after all that's done I'll make my decision and buy something.