Thanks as always Andy. Looks like I might have to go down this route - don't want to constantly be changing Rev G DVs every few months! That's just going to annoy me and can be costly in the long-run.
Are the GFB's a good long-term solution? Where's the best place to get them from and I need help with fitting instructions? Who else has done this and what's your thoughts?
Well I don't know too much about them, but this is what I do know. The original design didn't fare well. There were (are?) also copies of the valve knocking about that wouldn't have done the brand any good at the time. GFB took a bit of a slating, but apparently took on board this feedback and revised the valve. Most, if not all accounts of the revised valve on here at least are positive.
There is an info sheet from GFB regarding the issues and subsequent revision on here somewhere.
I did hear that Niki was testing the new design, but didn't hear much else. I have heard that he didn't like to map cars with a Forge dv - whether the older GFB valve was one he also shunned I couldn't tell you.
However, I will ask him about this when I see him in a few weeks and let you know what he thinks to the newer design.
Also if anyone else has any info regarding the GFB DV+ revision, please chip in or post a link!
In the meantime I'd advise giving your rev G a look over, check it for splits, and get a scan done to see if it's logged any error codes. Probably better to see where you stand before you start buying new bits, it could be that the dv is fine and the power loss is caused by something else.