A couple bits of info....
First Bit: My 2006 2619, unlike earlier model years, would require cutting and welding to add the lift kit, because the axle is mounted via welding. It's no longer bolt-on. (There's a small chance that this applies only to the 5000 lb axle). I don't know if this is a result of TM switching to the Torflex, but I'd guess that it is.
The message to be heard is: If you have the lift kit done AT THE FACTORY, you save about $150-$200 worth of welding.
I had originally decided to have the TM delivered without the kit, and then check if I had enough room (because it was gonna be very close). If I had known that it is no longer easy to add, I would have gotten precise figures so that I could make my decision before the TM was assembled.
Second Bit: On the 2006 model year 2619, Ground clearance with the standard 14" wheels/tires (3500 lb axle) is 8-1/2". Moving up to the 5000 lb axle and 15" wheels/tires raises ground clearance to 11-1/2". Even though the tire is only 0.8" bigger in radius, the 5000 lb axle adds a lot of height compared to the 3500 lb version. (I decided, just today, NOT to have the lift kit added... because it's now so expensive and time consuming to add, and because the axle already makes such a suprisingly large difference. And BTW, the lowest part is the bottom of the Sewer valve).
Third Bit: Note this interesting point from many other posters... for lots of people, it's not the Ground Clearance Instead, it's the Approach Angle: You go up a steep curb without the lift, your rear bumper drags on the pavement. The 2-axle 3326, even though it has poor ground clearance, has a pretty good approach angle, because there's not as much overhang as the single axle models. I''ve no idea how the 2720 max approach angle compares with the 3124.
