If I was to choose it would only be the kit in the first video, it seems to capture the curves and lines better. I would imagine it’s not cheap though. Do you have the price for these?

Denso

 

Perhaps this kit is the closest to keeping the OG TT stlying;

ALSATEK - Composite Technologies

High-quality and fitting composite products made of CFRP and GFRP.

www.alsatek.com

Not all seem to be listed as for-sale, so You would have to contact them directly.

These kits seem to be still available;

Body kit for Audi TT 8S for Audi TT mk3

Monsterservice. Body kits for cars

monsterservice.pro

Or there's the Swanflight Cup Aero kit, which includes a bonnet too;

Swanflight Audi TT Cup Aero Kit

Swanflight Audi TT Cup Aero Kit Kit consists of – Front Bumper Front Wings Side Skirts Rear Arches Bonnet

absmotorsport.co.uk

Or a Carbon Fibre arch kit;

AUDI TT 8S MK3 Carbon Fiber Parts – Widebody Upgrades | RSI c6

Upgrade your Audi TT 8S with carbon widebody kits, splitters, diffusers & forged details. Lightweight performance. Worldwide shipping by RSI c6.

www.rsic6.com

There's not too many about sadly, I'm guessing that Audi nailed the styling and the TT is so damn gorgeous it's a case of it ain't broke...................

 

Now this is PHAT for-sure!

 

I have never seen a car that looked better following the addition of aftermarket styling additions, most look like failed auditions for fast and furious movies, each to their own though

 

The Alsatek wide arch kit is my favourite so far;