If you want the max sound without upgrading the exhaust, catless is the way to go but of course you have to deal with the fuel smell and CEL.
I like catted better, the midrange has more volume and the high rpm sound is clean. the raspy catless sound is not for me.
it's a big difference in volume, but also an increase in raspiness and fuel smell.
If you already have upgraded your exhaust and went with a high-flow catted downpipe, and you still want more sound, catless is the next best option.
I have done flash tune and JB4 (different cars), and Im more inclined to recommend the JB4 for 99% of my customers. So much easier, less complications and still gets the job done (also cheaper).
I spoke to PTF about why they don't do this in the States, and they told me it takes years to break the code, and once it's released in the open, other companies will copy it within a month.
So it's not worth putting all the money, time, and research for other companies to copy it.
If the CEL is a concern, just get the active autowerke.
lots of brand make claim that it wont trigger the CEL, but if they dont give you a guarantee then they are not 100% confident of their claim