I was going to link to the BF owners group, but looks like one needs to be a member to access. I will summarize the post. BF changed their 17 foot trailer in 2005 to the 17.5. OP thinks it was updated to be better equipped for winter with enclosed tanks and double pane windows
. There were small changes in the interior and floor plans up to 2005 but mostly cosmetic.
In 2005 the 17.5 CB front dinette changed to a narrower seat on the door side compared to the bath side. They also lengthened the kitchen cabinet to give more counter room and create taller cabinets above the counters.
The closet also grew by about 6 inches in length. The bath remained the same. The fresh water tank was moved into the trailer under the rear couch (likely done also in the few years pre 2005 to allow winter camping.
The walls are 1/2 thicker in 2005 and newer to give better weather insulating . Also the dinette windows
were made taller, and narrower to accommodate the narrower dinette. Gone also is the overhead cabinet joining the front overhead to the bath wall. Tank sizes were in creased slightly with the 2005 and newer 17.5s as well. Trailer coupler went from 2' to 2 5/16" for the extra weight
We saw a 17.5 center bath only once and thought the rear couch/bed wasn't any wider than our 17, only 42 or 43 inches. We make due for sleeping but assumed the 17.5 would have a wider rear bed in the center bath configuration. Can someone with a 2005 or later verify this bed size? The winter package was available on our 2003 but our water tank is under the trailer, perhaps because it isn't a 4 season trailer? Wondering when the winter package was first available. The BF thread also had pictures of the 17 and 17.5 and the top shell is noticeably taller on the 17.5 than the bottom, allowing for taller windows
. The pre 2005s (17 footer) halves are about 50/50.