Some interesting points made Rich.
Space - Brian's light coloured interior does help; however, the biggest difference will be from the extra 6 inches width over the S1 cabin. When I drove an S1 I found it on the cramped side (I'm 6'3", 15-stone and have broad shoulders).
Surfaces - the grass is always greener

- I really love the individual feel of the S1 dash and hope MMC will find a way to improve aspects of the Aero 8 dash when the car gets a proper face-lift (no pun). For instance, the stock stereo doesn't suit the bespoke nature of the car and the dash clock that the driver can't see always seemed pointless to me.
I'm glad Brian jumped in and confirmed his shag pile carpets aren't OEM! I was ribbing him when he ordered them about the amount of dirt and muck that is going to get stuck in the pile

. The stock carpets are excellent and work well imho (leave the 70's shag for Austin Powers AKA Aeroman

)
Visibility - It is good with top down (although I still used to crane my neck over the dropped hood to change lanes) and top up not too bad; however, I to wish the rear window was glass. Plastic feels cheap and scratches/creases far too easily.
Doors - imho, after seeing the Aeromax, the best change ever - in terms of making the Aero 8 feel like a top quality product - will be the flush fit, Superform, doors. Precision, quality and style all with one change.
From the Outside - Yes, the S3 is 6 inches wider in the cabin, so this means the front wings are reduced in over-hang at the cabin edge over the S1.
I have gone on record to say that had the Aeromax front end not been put on the S3 Aero 8, I doubt I would have ever bought one because I didn't like the cross-eyed look; however, since owning the S3, the S1 has really grown on me. Now I actually love the S1 styling - although I do acknowledge that it is love or loathe design - and find myself torn between the purity of the S1 and the improvements in usability of the S3 (including the design).
Wheels - the most recent wheels are my least favourite, the Gen 1 S3's (and S2s) being my favourite (followed by the function before fashion S1 magnesiums). As wheels are such a matter of personal taste, I hope MMC decide to offer 2-3 options in the future.
Thanks again for the excellent run-down Rich on your opinion of S1 vs S3
