When you mean safely - do you mean if it will pass inspection? or slight loss of backpressure?
Of course to take full advantage of the mod - you will have to reprogram the computer. But you only do that once you change the filter, intake, etc. That is when you take full advantage of the mod and horsepower gain.

 

Thanks dok. I meant if you change the resonator (which presumably contains secondary cats), you will massively reduce backpressure in the system and hence some sort of air/fuel ratio changes may be necessary to enable the car's map not to run too lean or rich? So there are people who change only the X-pipe and/or rear mufflers and not adjust the car's map?

UK tuners are quoting a 100+ bhp increase from an ECU remap alone without changing any exhaust/filters/induction. With filter/downpipes I'm sure you could get close to 700bhp but not sure what sort of torque levels are safe for the gearbox.

 

Well, keep in mind. You already have 4 cats before the resonator. So resonator mostly just quiets down your exhaust. Your 4 cats in the front of the resonator keep most of the backpressure. I have done X pipes on american cars without any engine lights coming on ever. I have not done that on german made cars yet.
Just try it. Just dont weld the pipes. Use the clamps so in case if you want to put back the resonator all you do is loosent up the clamps and have your resonator back up. Experiment a little. I dont think anybod removed just a resonator on this forum keeping the rest of the exhaust stock. I have not found a post yet. Usually most people just change the cat up to the resonator or everything after the cats.

I would love to hear a soundclip of the panamera V8 wihtout resonator. Is anybody running that kind of setup?

 

Yes this is what I was thinking. Keeping the downpipes and back boxes stock and changing only the X-pipe. What puts me off is that the price of X-pipes is almost the same as a lot of full exhausts. The second issue is I want a plug and play system. I really don't want to cut and weld anything. Not sure how the original sports exhaust is designed but I am assuming X-pipe fitting isn't a straight forward swap? (i.e. there is cutting and welding involved).

 

Pdk can handle 715 tq or so before going into limp mode. Dodson has just released their pdk sportsman gear reinforcement that claims to handle up to 1400.

 

To replace just the mid / xpipe section - You will need one cut (mid from the muffler section but not from down pipe)... The xpioe is 1.5k. I would replace the whole system if I were you along with with a valved aftermarket axel back and a tune. They sound amazing when completed