Don't forget, VWRacing do NOT have any official ties with Volkswagen UK or Volkswagen AG. They are just another private tuning company, just like Awesome GTI, Regal, JKM or even Demon Tweaks.
....Is that so? - Well, VWR/RacingLine state that they have 10 years of building the 'works' race and rally cars for Volkswagen Group UK and have a unique relationship with the factory in Wolfsburg. They are absolutely
NOT "just another private tuning company, just like Awesome GTI, Regal, JKM or even Demon Tweaks." as you claim. Have you had any direct dealings with VWR/RacingLine at all T_T? - If you had, I think you'd know that they are very different indeed from the companies you mention.
But, be that as it may, there appear to be some differences between the various engines as already discussed and who am I to question those who have such an intimate knowledge of all those ETKA numbers. I'm not 'qualified' to take part in that debate.