I recently bit the bullet and bought the TSS handbrake Sparco mod, even though there is no "official" PS4 support. (It was this or another TH8a shifter)After a short round of testing with Dirt 4, dirt rally, SLRE, Gt sport, WRC 7 and Pcars2 I am happy to say that it works out of the box!
I have not made any firmware updates and just plugged it into the wheelbase Din connector and the TH8a into the ps4 usb port and it actually works really great with games which support USB devices, however support is varied:
Dirt 4 & GT sport
The TSS handbrake is detected in both SEQ and handbrake mode in both games. In Seq mode it acts like a TH8a in seq mode and mapped as r1 and r2. In handbrake mode it is recognised as a separate (handbrake) device.
update from Polyphony explaining "official" support:
https://www.gran-turismo.com/gb/gtsport/news/00_3641113.html
Dirt Rally, SLRE & Pcars 2
The device is not recognised in handbrake mode, but works in seq mode. It is detected as a TH8a in seq mode and mapped as L1 and R1. Sadly it isn't possible to use both the TH8a and TSS in seq mode. Since both the handbrake and shift paddles are mapped to to L1 and R1 you cannot map the handbrake as a handbrake and still use the paddles for sequential shifting. There are 2 workarounds:
1. You can use a TH8a in H mode for shifting and map R1 as a handbrake. The TH8a is mapped in these games as gear1,2 etc. The downside is you wont have sequential shifting available. You can setup the TSS handbrake as a handbrake and keep the toggle switch on seq. That way a handbrake is mapped as R1.
2. You can use a rubberband mod to use the TH8a in H mode as a handbrake and use the TSS as a seq shifter (R1 and L1). Either map gear 4 or perhaps gear 2 as handbrake in the settings.
example of a rubber band mod:
WRC 7
Sadly this game only supports 1 TH8a connected to the base, also only in sequential mode and there is no support for a separate usb device. The TSS is detected and mapped as L1 and R1. You can either map sequential shifting to another button and R1 as a handbrake, use automatic shifting and map R1 as handbrake or use the TSS as shifter and use a different button as a handbrake (default).
Assetto Corsa
@Lirol confirmed the TSS works in handbrake mod connected to the wheelbase.
With the 2 newest games on the list already supporting the handbrake I suspect official support is coming soon and future games will support the game.
sidenote: I use a powered 7-port USB hub for: Wheel, cpx adaptor, TH8a, Sony BT headphones, PSVR.
Hopefully this answers some questions some people have who are interested to buy the TSS handbrake sparco mod on PS4.
Edit: updated with link to Polyphony support for TSS handbrake
Edit 2: anouncement by tm on Facebook:
Edit 3: Confirmed support to Assetto Corsa