I have a 2005 with a JCW tune and I am wondering if a different tune might work better. Has anyone replaced the stock JCW tune with an aftermarket tune with good results?

 

The biggest difference is that the factory tune is focused on federal pollution guidelines. If it's an actual JCW car then you're already running an 11% S/C pulley. A 15% or 17% pulley and an aftermarket tune will make quite a difference in the performance of your MINI.

 

^^This^^
Yes, if you're looking for performance, a custom tune, even with the same parts, "can" give you an increase, sometimes even in MPG since the ECU will then be "fine tuned" to you're specific parts.

But, be aware, it could be a big gain, it could only be a small gain, it really depends on how the factory tune is working with "your" parts. This is why the second part of the other post may be something to consider first if your looking for maximum gains.

 

Thanks.

It isn't an actual JCW if by "actual" we mean "factory installed", but it does have the full kit dealer installed - head, pulley, injectors, brakes and tune.

If a tune is going to make a difference I'm happy to give it a whirl. Is it possible to go back the the JCW tune at some point?

 

Yes, that's an official JCW car and tune, most if not all JCW Kits were dealer installed.
(I can't remember if they ever actually came from the factory itself, it's been a while)

Shouldn't be an issue, most if not all "good" tuners will save the tune file that is in the car now, as a backup.
but it's especially not a problem with a known factory tune such as you have.