It's not only full stainless and immaculate, it is also 4.4kg lighter than the current system. Weight is king 
Here's the current system, which uses an Aprilia muffler.
As with all things kit car, the exhaust is pretty easy to break down.
The Westfield muffler waiting to go on.
It's longer but narrower and has a Cat in it (currently..) and in theory should be a tad quieter than the Aprilia.
Test fit to the existing mani to see what the noise levels are like.
It definitely sounds deeper on idle and at low revs. The plan would be to remove the Cat, which should improve flow but will probably make it louder 
Time passed and I found some more time to fit the whole system.
First up I had to remove the passenger seat, as it allowed easier access to mount the bolts for the plate. Bit dirty in there though 
Some coming out, some going in.
I couldn't live with all those bits, so had at it with the vacuum
The old headers.
It basically slots in and is secured by four plates and some bolts.
Relatively easy to fit and remove, so long as you get your access angles right.
The new.
Mmmm, clean 
Mounted.
The full system on.
There is an issue however... It doesn't sit flush up to the bodywork and required a fair amount of effort to mount it, which I'm conscious will strain the welds and eventually cause them to fail after several heat cycles. I think it's going to have to come off and either be cut and welded or...? Sounds good but I think I prefer the sound of the Aprilia. That could be down to the Cat being in though. The other key benefit of this system (besides weight reduction) is that it doesn't blow exhaust gases directly onto the rear wing, unlike the Aprilia, which has caused the carbon (well, the resin in the carbon) to come apart 
If for whatever reason I stuck with the Aprilia system I'd need to find something very heat resitive to cover the rear arches 
Next up was to mock up a cover for the dry sump pulleys and belt.
It was a little exposed and ran the risk of a stone potentially bringing a halt to oil flow and ultimately the engine 
So off with the Donkervoort nose, which the eagle-eyed amongst you would have spotted isn't a stock part 
See, somewhat exposed in there.
Although the undertray does help significantly.
Out comes the spare ali sheeting from when I was fabbing the undertray and arches for Mule v2.
A session with the tin snips, a block of wood and rubber mallet later and we have the first cut and bends.
A little bit more and we have the rough shape.
It's longer on the top, to act as a cover and stop when it meets the engine. My logic was that even if it did flex back a bit (towards the engine) having a longer flap on the top would stop it hitting the belt and pulleys. The bottom will be bolted onto the frame, so no movement there.
A test fit.
The blue is the protective plastic film, if you were wondering 
That's all I've had time to do until now.
Swapped a couple of pipes, fixed an oil leak (nearly catastrophic!) and made a few people have Vanilla Ice haircuts from rides out in it 
Good excuse to have a good clean too.
