Vee1990

Im not sure if this is the right place to post this but here goes, I have an 06 E55 amg, i recently installed some short Kleemann headers on it, the car has no mufflers and resonator, before the headers i ran the car with the same setup and it ran strong.
The same setup being, muffler delete, cat delete and resonator delete stock headers. After i installed the headers ive been experiencing a whole slew of problems, first gear is responsive after that the car has almost no acceleration even if i put my foot all the way down to the floor
it accelerates at the same pace. There is a fluttering/ticking sound when i accelerate coming from the bottom of the car and ive been assured there is no exhaust leak, there is also a vibration at the bottom at low rpm's when accelerating aggressively. When the shop installed the
headers they also installed a pair of hi flow cats and new spark-plugs, the cats where installed without my knowing, could they be the issue ? Ive reset the ECU both with the sneaky ECU reset and disconnecting the battery overnight. Please help, thank you guys in advance, cheers!

Header Link: https://ebay.to/2Qac9So

MACEDON

Have you tuned your car for the headers now?

Check if the collectors are tight again

The thin headers will sound a little louder my friend, so it might just be that.

Vee1990

Thank you for the info, im just not sure what you mean by collectors, can you explain that to me please?

Thank you!

Strigoi

The collectors are the end of the headers where they connect to the rest of the exhaust system.

PieRat

Where the 4 pipes leaving the engine merge into one big pipe like the boyz have said.