As far as I know no one has done this as of yet only without cats !
Thx Steve-Gotcha, I am considering the upgrade but worried about passing emissions. Not sure if itās worth it with just the high flow catsā¦as far as performance gains.
No doubt some high flow headers would increase power/flow over stock but proper install for fitment would take a good shop as itās a tight fit. JHM Headers not only get rid of the Cat restriction but they open up the tight bend a little that the OEM Cats cause.
Thanks!
Makes senseā¦just would love to know how much improvement before laying down the moneyšā¦it seems to be worth it on the catless version that you guys have done.
I have a shop in mind that has a solid reputation at leastā¦I was not pleased with the shop that did my jhm exhaust.
Mine is a little tricky because I have a cabriolet and it had to have a spacer kit installed to get the exhaust to fit over the extra structural bracing. So it might really be a tight fit!
Yea, forgot about it being the Cab and having to route around the Chassis reinforcements. Should be something a good shop can work with though. I wonder if JHM or somebody can estimate what the cell count of the OEM Cats are? Compared roughly to a 100, 200, 250+ cell Cat?
That would be interesting/usefulā¦I just hung out with a guy, rs5 owner, that has headers and castles that passed emissions by putty by a spacer between the o2 sensors? And maybe a couple of other tweaksā¦
Mark, is your car up and running with the JHM goodies?
Looks like itās not be yet. Car was getting itās paint today but the guy didnāt want to repaint the roof/door window drip moulding so Iām ordering new stuff. Ordering Black and itās about $450 per side. There is a rubber seal on it so might as well as install new stuff since the old stuff is 8yrs old and it wouldnāt be that much less just to tell him to paint the old stuff. I may pick up the car next week without the moulding since the flat (not shiny) Black trim may have to come out of Europe. Also still waiting on the JHM rear exhaust section to mate up with the front JHM portion, ordered on 12~13 Apr so hopefully theyāll be done soon.
On a plus not I did replace the center support bearing (yea, the bearing itself was bad on my conversion axle) on the propshaft for my manual converted RS6. After converting it to a manual it was even more of a beast but had this whining sound and I was afraid it was the transmission. Decided to check out the propshaft and there was a small amount of play in the center support bearing plus the rubber was deteriorating. Audi doesnāt intend for you to rebuild them but companies do sell the parts (034 in this case). I ordered a rebuilt shaft but was successful in getting mine apart. All is fine now, itās a Torque monster. Did around 500 lb/ft to the wheels on the dyno last year, must be around 600 lb/ft at the crank. Thatās what twin turbos do for you 
That sounds ace 
I had an RS6 V10 quite a few years back and that was a monster.
I was running 730bhp+ with over 1100nm of torque so twin turbos do make things into a monster, I loved it !!!
I replaced my centre bearing on mine as was getting a clunking sound when on and off the throttle, if I was hard on it then it would bang quite badly.
I know Audi donāt sell these separately and only as a complete propshaft and they are 1600.00 pounds in the u.k from Audi.
You done well to split yours and change the centre bearing yourself, I know they can be tricky to do. I found a company in the u.k to rebuild mine and i found another company that made centre bearings for Audiās cost me about 350 ish in pounds in total so a good saving.
Iāve actually got a whole spare fully rebuilt propshaft now I found a low mileage RS it had only done12000 miles it cost me 250.00 pounds for the propshaft and I had the centre bearing changed just to be sure and then got it all balanced up !
@adaydreams I live in The Netherlands and the RS specialist shop here has done multiple 100/200 cell race cat convertions for customers. He checked my cats and theyāre still good, but if they are on their way out Iām going for those 200 cell cats as well instead of cat less. Main reason being emissions tests in The Netherlands. He didnāt mention power figures, but he did say it allowed the engine to breath a little better. Iām sure catless gives more gains in performance, but like I said, I donāt want to risk failing the yearly emissions test.
Iām sure a 200 Cell conversion if done with the same or hopefully better bends than the sharp factory bends will be a big improvement. The OEM Cats are a short/fat design in order to fit and they had to make a couple of fairly sharp turns in the exhaust flow to make it work, so the JHM header mod not only removes the Cats but it reduces the bends which also helps the flow.
You could probably install the cats where the factory downpipe resonators sit, it will need some extensions to the post cat sensors but thatās not a difficult task.
Iām running the AWE resonated downpipes and they a good size larger than the OE resonators so itās very possible.
James is right. The reason the factory installs them so close is to heat them up faster as OEM emsission tests start at startup. If they are down stream theyāll be plenty warm by the time you get to a testing station, or if itās real close just go on a 15min drive prior to testing so they are hot and more effective.
I used to have a 5 cylinder turbo Fiat Coupe with cats at the bottom of the downpipe, it would always need an āItalian tuneā as the guys called it at the test centre before it would pass the emissions.
Turbo cars are worse for this as the turbo sheds quite a lot of heat from the exhaust gas.
*Italian tune comprised of 3 sprints down the road of the test centre to get some heat in the cats.
Thanks for everyoneās thoughts! I have an emissions test in August and then am good for two yearsā¦so I may get those headers and the 200 cell high flow cats just in caseā¦.hopefully they can install them down further as I have a cabriolet and there is some extra bracing underneathā¦and if I canāt pass emissions I may need to look up an old friend in Montana and get set up where they donāt test, 
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I know it is 2.5 years down the line, but could you pls share the name of the RS specialist in the Netherlands? I am looking at gutting the OEM exhaust header catalytic converters; I dont think I can send my exhaust headers off to the US and JHM for 3-4 weeks.
I am wondering if they gut them or do engine out only.
Sending you a PM!
I have this setup amongst a few other mods but this video of my dyno Run will give you a good idea of the sound: