If you are contemplating a rim upsize, going all the way to 16s can make a lot of sense.
It appears that you have plenty of room to do so.
You only need 1" spacing between the tires. And 3" from the top of the tires to the wheelwell.
Going to 16s is easiest if you presently have 6 lug rims... Not likely if you now have 14s.
I was in your shoes on a previous TT. I eventually got to 16s after spending a LOT of money on incremental upgrades. I hade 3500# axles with 5 lug drums. I found that 6 lug drums could be swapped straight over. They used the same bearings. New drums were suprisingly affordable.
They even came with new bearings. I made the swap at bearing repack time to make it easier.
There have been some that have been able to find 16" 5 lug wheels. They were not around when I did it. I also haven't looked at the total advantage/disadvantges of that approach: How widely available are they if a replacement is needed? What is that cost compared to the cost of doing what I did?
If you can go to 16"s, it opens up a vast array of tire choices, that may well make any cost for the upgrade doable, or even pay for itself overtime.