Umm... let's see, DragonBob has been running this filter for a long time, including trips to Moab. I think it's okay to run this filter.

AMSoil is good and I have nothing but praises for them. Customer for 6 years and probably the only oil I will buy. But, they don't have first hand experience with the VX.

The factory filter is really too small for a 3.5L motor. A 2.0L turbocharged Mitsubishi motor's filter is about the same size if not slightly bigger.

AMSoil is telling you that it *might* not be a good idea to deviate from factory specs because they don't want to be liable for damage caused by improper use of their products. Gotta read between the lines. Their conservative recommendation is based on speculation. DragonBob has already proven that the larger filter will work just fine.