playing devil's advocate for a minute, are these the same Forge tests that show no power loss with the DV spacer? as i'm sure you can appreciate RR it makes sound business sense to sell two identical items but one for £100 more and try and convince the buying public that that extra £100 is worth it as they're somehow getting more.
even if Forge's tests are right, what sort of extra power are we talking? 2-3bhp peak power? i remain cynical tbh.
....Nothing wrong in playing Devil's Advocate - In fact it's good for the forum when posts are challenged (if done so
politely and without calling each other stupid).
At the time I discussed (in numerous phone calls) the Twintake with Forge there was no intention on their part to offer a single pipe version. The single pipe version at that time was just an additional prototype to see if the more expensive to produce Twintake was the best way forward. Without sufficient gains, Forge said they would not produce it - That applies to most aftermarket performance product manufacturers.
I'm afraid that I don't remember the exact performance comparisons and I don't want to stab at it and get it wrong.
I take your point about Forge's DV spacer but don't know enough about it to comment in depth but suggest that if it is a widespread common problem, why hasn't the product either been withdrawn or modified? Do we know for 100% certain that those reported were properly fitted?