Pete,
Glad you enjoyed the experience. It may be worth checking the owners list on here because you may find the S3 you are looking at was owned by, or known by, someone on TM.
The chaps have covered the topic well; however, whilst I am not qualified to judge Plus 8 vs Aero, I can say that touring in an Aero is very easy due to the lockable boot, window configuration (no need for side screens) and ability for the Aeros to cover long distances in comfort. I have toured in an Aero and done circa 6,000+ miles combined - I have never once found myself wishing I was in another vehicle.
I wish you the best of luck in your search and as long as you buy a well cared for example, I am sure you'll enjoy the ownership experience immensely.
