I have an 07 GT3 with sport chrono and NAV.

If I yank the PCM to swap it with an aftermarket unit, exactly what features am I giving up?

 

My 997.1 does not have sport chrono...but, I can tell you from chatting with people who did the aftermarket nav system with sports chrono, what you get is what's available through the stalk on the steering wheel.

In other words, the chrono works, trip computer and all that...but whatever you were able to only do through the PCM is gone.

This is not to say that the Porsche dealer couldn't reprogram these features for you...you can't do them yourself any more through the PCM ( cuz it's gone)...

By the way, I ended up selling my PCM for almost a grand... Paid for 1/2 the Pioneer unit and install.

The PCM 2.1 is totally outdated and can easily be replaced with an aftermarket unit that blows the PCM away in every way.

 

Thanks Steve. I need to determine exactly what I'm losing to see if I can live with that. I'm pretty certain I will lose the sport chrono feature altogether.

I haven't been able to dig up any posts from people how have done exactly what I'm considering with my options.

 

If by sports chrono you mean the clock timer thingy on the dash, you will not lose that function at all...it will still work through the stalk on the steering column....

This has been proven by someone on here who had that feature...I remember asking him specifically as I was very curious.

When I bought my 997, I made sure to buy one without that feature as I knew I'd be yanking out the PCM...