When you say spline based modeling, do you mean creating a spline and then converting to editable-poly and then doing the extrude or lathe? Or can you some how extrude a spline without converting? I just don't know how you model all of those curves and corners and have a clean mesh with surface subdivision, and then to make each part fit together smoothly after modeling. I model almost exclusively with polygon and subdivision and have not had enough time to venture into other techniques like I want to. I would not have even thought about trying to model something like that with those techniques but I guess it can be done.