I can tell you that the 355 front bumper is a bolt on for the 348. My guess is that once you have changed the bumper, the undertray will fit correctly (same chassis). Without it, (i.e. keeping the 348 nose) most likely you will be looking at some mods.
It would take quite a bit of work to make the panel fit. There are no attachment points on the 348, besides the front panel is part of a complete under panel set. if you were to put the front panel on you really need to fit the rest and as I said it would be a lot of work. Also the rear panels attach to bumper on the 355.
