Review of NP Boosted N63 Catless Downpipes ($179) - with Dinan Stage 3 Tune


Apr 19, 2017
335i e93
OK, this is a review of NP Boosted N63 Catless Downpipes with a Dinan Stage 3 Tune.

- Dinan Stage 3 tune before catless downpipes was better than stock tune and you could feel it.
- Add the NP Boosted N63 Downpipes and the x5 50i changes completely.

1. Definitely louder - sound appears to emanate from mostly the engine bay - probably due to the lack of catalytic converter and the sound is no longer absorbed by the cats.
2. MORE torque, More power without any additional tuning or adjustments. - Dinan stage 3 specifically says that their Dinan Exhaust is required for that tune - but I think the catless DP is more and enough for their ultra expensive exhaust that probably doesn't free up as much air flow as the catless pipes.
3. Throttle response is definitely much quicker than stock.
4. Holy hell the turbos are loud as hell now...very loud swooshing every time you press the pedal.

VERY POOR FITMENT. Be advised, these pipes are not recommended for the weekend car guy and even professional mechanics will find them VERY difficult to install.
I had to cut parts of the drive side heat shield under the air filter box, cut out parts of the heat shield overlay on top of the turbos to accommodate the misplaced o2 sensor locations. The passenger side down pipe managed to fit after a very difficult and tight adjustments...but the driver side was ten times worse. It literally took me two days to get the driver side to finally get installed and it wasn't even perfect fit. I had stripped one of the bolts that I bought from Lowes, due to the fact that the bolts that they included were too big to fit in the stock exhaust holes. So I had to go back to Lowes to get extra bolts.

The driver side connection to the DP is extremely tight and has many obstacles in the way of your hands and eyes.

Finally, the driver side DP exhaust connection had to be cut in many slices like a flower petal and then I used pliers to bend each petal inward so that the connection would fall into place when inserting the DP downwards into the exhaust hole where the bolts fasten.

Do I recommend these DPs? NO. Absolutely not due to poor fitment.
The price was a steal, but now I know why...
The materials appeared good enough, but the bendy neck part didn't bend very much so that made fitment a nightmare. I wrapped the entire DP with exhaust wrap, and also That be all.
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