[Backstory: the Promaster’s cargo floor comes in 10’ and 12’ lengths.¹ The 10’ length is available in the lowest-run 1500 but to get the 12’ you have to get a 2500 or higher. I was concerned that although all the Promasters are under the magic 10,000lb GVWR number the underwriters would want to call the 2500 (or both) Commercial.]
I asked my current auto insurance agent to run insurance quotes by VIN on vans that were identical other than wheelbase, and nomenclature:
2016 136” WB 1500 - $1,204/yr.
2016 159” WB 2500 - $1260/yr.
The quotes she provided were for full coverage w/$500 deductible. The difference in cost of insuring them is negligible, and appears to be a function of the slightly higher price of the 159” rather than any new risk factors. This means the 159” is not ruled out based on insurance cost.
I am currently planning on the 136” platform, reasoning it would be easier to relax interior dimensions if a 159” dropped into my lap but not vice versa.
¹ They also come in 8’ and 14.something’ lengths but those don’t interest me.