[quote user="Kaz219"]
Hello.
I was looking into Decatting my A3 but are there any performance gains.....
I was also planning a straight-through backbox, then a CAI, then a Remap

...
Is this a good idea?
Cheers
[/quote]
All i would say is do it,improved throttle responce is the first thing you will notice,quicker spooling times,less lag,also will help with life of the turbo because the system will be bigger bore so less choking with no cat/cannister more free flowing keeping turbo temps down.I had it done on my gttdi 150 golf and it would be the first mod i would do with any diesel rather than people who start with things like air filters or induction kits what have been proved make a 0000.1% improvements at the most(improvised percentage may have been used there),they sound nice to me-not loud just a nice spooling whistle under heavy throttle