John Sims should be able to confirm for sure as I think he only bought a back box.
I did indeed, and it was a direct swap; although you do need to remove the existing rear hangers and replace them with the Janspeed ones provided. This does take a little working out but, with two of us considering all options, my honed craftsman mind solved the puzzel.
I had mine fitted by my favoured Independant, who charged me a mere £25 and was worth every penny - he didn't even charge any extra athough I insisted on "helping". We were in the warm and dry, the car was at a convenient height and they were able to get a torch to the stubourn existing hanger nuts. I would have probably resorted to the two foot breaker bar (I'm not keen on using a blow torch near the petrol tank) and would have destroyed the threads.
You might be a little disapointed in the aural experience initialy. The Janspeed system was designed to pass track day noise tests and consequently is only marginaly louder than the standard system - the difference being from 94 on the original to 96dB A if I recall correctly. Rick did a comparison at a the last 944 Brooklands gathering. I think my 220 non cat ESS back box was 96 and Tony's decat 250 was 97 - either way the difference is marginal.
I didn't notice any difference in power but then, perhaps, 5 bhp on top of 250 isn't going to be that obvious anyway.
The big oval fills with water, the best part of a cup full, and consequently you smoke like a steam train after washing the car or if it has stood in heavy rain.
So far there doesn't seem to be much in its favour [
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Where it does score (aside antagonising those with baseball caps) is, when you get the exhaust nice and hot, it develops a lovely bubbling burbel on a featered throttle at low revs. It's cheap, is the other big plus point.
