Yeah I know what you mean img mechanic mate will swap them for £50 for mot don't think I would do it myself like you say to much hasslemore hassel in my opinion especially if you havnt access to the right tools. as for the DIY'ist getting the pre cat down pipes off can be a pain. swapping them over time again isnt ideal in my opinion
I use to run mine with the decat pipes I just ran it with the EML light on up until I got the JHM tune which then sorted it. Any company that can remap can get rid off the code tho. If you want to go for the JHM tune I currently have a flash cable which is being passed around so let me know if you need it and I can forward it on to you.
why remove both and then have to swap to get the car an mot
unless you are going for a very high stage of tune then there is no benefit to removing the post cat as the flow is more than adequate
the problem on s4,s is the pre cat not the post cat
gut the pre cat and either map the existing lines out with your current tune or
go for something like a ccc tech tune or jhm tune which eliminate the check engine light by opening up the parameters
Nice build! makes me miss and want another B6 S4! what headers are those? and how come you used the stock downpipes with them? albeit with out the pre cats of course