I'm sorry to hear that you had such a crap time at Secor. I worked in Groton for 2+ years, and never had any problem with their service department. I helped a buddy of mine buy a car through them, he got a great price on the car as well as his trade in Ford ZX4. Remember though, trade-in on a non brand vehicle is always going to be less. A Subaru dealership really doesn't want a SRT-5 on its lot any more than I want an SRT-5 in my driveway.
I can't imagine that he actually said to you "you're full of ****". Perception does play a large role however. Maybe next time don't show up looking like you're 15. You know you're more mature, but they don't. Would you buy a high performance or luxury car from a guy who was dressed like Larry the Cable Guy? I think not.
I expect we'll hear from Brian (I think that's his name) of Secor shortly. He peruses these forums under the handle "Secor Subaru"