Owning a 2013 M3W I went down the route to get a 4/4 later one.
I kept the M3W but for any trip longer than 2-3 hours I usually take the 4/4.
The "modern" threewheelers are just a bait to get you trapped into the Morgan world.
You will love the traditionals and enjoy their reliability (reliability measured in Morgan standards!)
You will miss the M3W but you most likely will not regret a change to a +4.