Ignition coil Bosch or Bremi

I'd replace the FPR with a 3BAR since they are cheap and easy to replace and considering your mods. New coolant temp sensors for the same reasons as well even though you state they are ok. Coil could be an issue, no real need to upgrade the factory ones but a new one could resolve the problem (Bremi coils are using STI [brand not car] windings in the units).

Just installed the new coil and the car runs great. Very pleased with the results.

Be sure to use a genuine Bosch from a reputable source, or OE from the dealer. DO NOT use a Chinese one from a big-box auto parts store.

Make sure the new coil is a good Bosch, Beru, or OE unit, not parts-store brand junk. I've seen plenty of bad coils out of the box.

I ended up getting a brand new Bosch ignition coil from German Autoparts for around $160 shipped with a few other small parts. This was around November last year.

Go Bosch, or Go Badly.

0,5l/100km less fuel consumption, consistent, and what is most important, my Golf was the only car that started by itself this winter at -30 C outside, among about 30 cars in our courtyard.

Many aftermarket coils are completely out of spec and do not work well, some can even destroy the ECU. OE, Bosch, Temic are all good, I believe Beru is an OE manufacturer as well.

Performance gains from only a coil, I don't know, probably none, however the car I have it in is completely stock in the engine department. As an addition to mods I think the coil is a good idea because it helps to smooth out these cases when mixture is out of stoich Maybe better throttle response.

Worthless cause it doesn't have an internal pin.