[longassname]

I would not recomend a piggy back system on an SVX most especially for forced induction.

The factory firmware in the SVX ECU has very little ignition timing in the primary ignition table and relies on an algorythm using the knock sensors to learn in additional timing up to a maximum specified in the ignition revision table. This system doesn't work as well as just specifying ignition timing for good performance in the primary ignition table even for naturally aspirated cars. It completely doesn't work on forced induction cars. The "aggressive" tunes which all the ECUtune versions are now were first developed to solve the problems with forced induction; we then found that doing the same thing with the stage 1's also gave much better results.

So if you are going to use a stock ECU use ECUtune firmware and forget the piggy back. If you want to do your own tuning you need a standalone.