All much the same, the Bayjoo chips were said to have a modified timing curve though.
Whether it was a myth or not but Turbosystems used a chip from a house alarm or similar for the RS Turbos!
I had my S1 for 6 years, rebuilt it after 2 as I wanted more power. Forged rods, pistons, (1,680cc IIRC) inconel valves, titanium springs & caps, Benneton F1 head port, 3" turbo back exhaust, T3 of an Integrale Evo, Forge actuator, custom intercooler, ECU done by Tony Mannock @ Turbosystems with (I shit you not) a chip that he sourced from a house alarm!!!
Thats how you change them , they are soldered into the ECU , I remember Harvey Gibbs doing mine back in the day.