[Schwarzeritter]

There are a lot of good piggy back system that are very user friendly.
We smooth over a 944 with the addition of a wideband oxygen sensor added too his aftermarket 1-off exhaust. Using a Apexi air fuel controller which was not bad too use ended up costing a total of 150.00 for the Airfuelcontroller. We for fun spent 45min on the dyno dottled with the timming.

However I would recommend something along the lines of a Piggy back as there alot more indepth and with paciants and time you can extract some very good numbers but you'll need too know how the Porsche factory ECU and how far you can push it with out upseting the ECU. However this is not as problematic as say that of OBD II cars.

I think the cost is about the same as most chips. excluding the 150.00 + you might spend on a dyno but you'll have a tune set up for you specific state of tune.