PureBlue:

After lamenting the disappointing sound from the GTS's PSE, I've taken the plunge and ordered an aftermarket exhaust specifically designed for the 997.2 Carrera/S/4/4S/GTS by SharkWerks in California.  Effectively replaces the central muffler (silencer) with two straight-through stainless steel pipes, for what should - by all accounts - be a far more satisfying sound.  I've had it approved by the local OPC (so no warranty issues) and they're even doing the fitment for me.  Should be arriving next week.  I'll post up full details, pics and some feedback as soon as it's fitted.

I contacted Alex Ross at SharkWerks and set up an order subject to warranty clearance.

Having spoken with two OPC's (Chester and Wilmslow), they assure me that using the product would most definitely invalidate my warranty.  Neither would be prepared to fit the unit for that reason. 
 
One of the service engineers I spoke with, at Wilmslow, used to work for Techart and stated that Porsche's attitude to 'After-market Mods' in the UK has altered a lot in recent years.  Also, in his opinion, the chances of a "check engine" alert would be high and often.. resulting in frequent visits to them for re-sets.
 
For those reasons I've chosen not to order.  Pleased for you that the situation is different where you are...but you may want to ask them about the "check engine" warnings issue?
 


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"Things turn out best for people who make the best of the way things turn out."