I had my ST170 from brand new and drove it hard everyday of its live for 56000 miles until i sold it and it never skipped a beat engine wise.

They need to be revved.

Bluefin, decat and exhaust and panel filter was all i done to mine. I didnt need the MIL elimiantor as my engine warning light never came on. Well only once when i did a jump and broke the manifold and lambda sensor off

The bluefin made it rev a bit more and seemed smoother with it but no real notacible power gains from tbh. As are the decat and exhust also it was just a nice note rather than power gains.