Would like to make a review of the products as well as the customer service of Jamie in particular.
Summary - High quality products paired with superb customer service - highly recommended!
Just a brief background on the car:
2007 997.1 GT3RS with Evoms / Sharkwerks header (200 cell cat) - stock side muffler and titanium 997.2RS centre muffler. Evomsit flash.
Car has about 35000 miles and I intend to keep it for a long time to come. Decided to install the harmonic damper, although the harmonic issues are supposed to be less problematic in the 3.6 cars - would like to have peace of mind and if in future I were to consider upping the capacity - there will be less worry.
Ordering / Payment / Delivery process - Jamie is prompt in answering all questions and no pushy at all. Tried to tempt me for the long race headers - but its no go in my country due to the strict regulations here. Jamie kept me updated on the built process of the airbox and shipped both items once the airbox is ready.
Installing the harmonic damper pulley - no issues at all.
Carbon Airbox (dual cone / single inlet) - nicely made and came in a sturdy wooden box (no worry about delivery damage). Noticed no cutout to accommodate the engine compartment fan. After initial installation - upon test closure of the engine lid, realised that the engine compartment fan will interfere with the airbox preventing closure of the engine lid. Messaged Jamie - who told me there were no interference issues with the other 997.1RS he had. He suggested cutting the support spacer on the lower part of the airbox. Tried that - still having issues with interference. Jamie was in the process of ordering an aftermarket low profile fan for me when he realised that there are 2 stock OEM fans. The newer ones are lower in profile and eliminated the interference issue.
He promptly order the new fan and had it shipped to me after he received the fan (fan was not available locally).
After installing the new fan & with the lower spacer height (by 1cm) - there was no interference - but I noticed that the rubber piece that seals the airbox from the intake opening is not flushed with the airbox. Returning to the original spacer height made the seal flush but had a little intereference with the connector of the fan which can be resolved with a file within a few mins (non-consequential part).
Subjectively car feels smoother and more torquey. Having only driven the car in city traffic so far after the installation, I can feel the car being smoother and just generally nicer even in the lower rpm ranges 2.5-4.5k rpm. Haven't have much chances to go beyond that to make even a subjective opinion.
I usually drive the car in the non-sports mode (exhaust valve closed) in city traffic - as I like the intake / mechanical noise over the exhaust noise. In the 2.5k - 4K rpm range - the intake noise is definitely a little louder and more melodious. My wife described it as "the car sounds different in different gears". All in all - it made the car more enjoyable to drive even at mundane speeds. Hopefully the change is even better in the upper rpm ranges.
So here is my final review about these Dundon headers:
- First of all, these headers are beautiful.... they look so good that I just want to hang them on my wall. A quality product! Comes packaged nicely with a set of K&N filters.
- Install by the shop was smooth like a breeze, no fitment issues at all. Took around 2 hours to install
- Initial startup: car sounds stock!
- Initial drive: Under 3k RPM the car sounds completely stock. Over 3k you could hear something angry lurking waiting to be unleashed, and all the way to redline is described as INSANE, my ears are bleeding!!
- Dyno procedure: I was instructed by jamie to follow their dyno steps. Fans at inlets, blocking off radiator heat, monitoring IATs and do a couple of runs.
My stock run showed a 344whp baseline with a respectful IAT.
After that I drove the car for another 100km and came back 3 days later for a post headers dyno.
The post dyno read around 374whp, which showed a massive 30-32whp gain around 5000rpm and a massive 37whp gain around 7500rpm. IMPRESSIVE on a N/A car.
The car is otherwise on stock tune with just BMC filters and 98 octane fuel.
Car runs smooth with no CEL or any warnings. The sound is exotic! Has a nice and loud bark and the downshifts are just plain brutal.
I would like to thank Jamie from DMS for his constant support and for a quality product from DMS. ~ Kareem, Bahrain: GT4 Race Headers