Instead of continuing to hijack another thread, I though I might start a new one on this topic.
Delkevic downpipes are beautifully made. Mandrel bend 1-piece pipe with machined plate. 32mm constant diameter is exactly the same as stock down pipe. Again, as I mentioned in the other thread, this will have the same characteristics of keeping exhaust gas velocities high at lower RPMs, which aides part throttle response and midrange torque, at the expense of top end HP. Whether this is good or bad depends on what the rider wants. For me, the Ninja 1000 is not a track bike, so I would rarely - if ever - venture near redline. Top end HP is of little concern to me. Kawi factory engineers selected this size downpipe for good reasons, as it suits the purpose for which they designed the Ninja 1000. I agree.
Lextek's downpipe is a real curiocity. It is made of the same 304 stainless steel as Delkevic. It starts out at 34mm, then flares out to 40mm via a welded cone section. Don't really know why they bothered to do this, as keeping it at 34mm would probably not change the power characteristic too much. But... it is what it is. Build quality is below that of Delkevic, with welded sections where Delkevic has mandrel bent. Fit is not superb, and it appears Lextek knew that, as they included adapter plates for the link pipe attachment point, as if to say: "you'll have to work out the final position, once fitted to the bike."
And... the link pipe exit was angled a bit too far in toward the tire. Okay... I bolted the can down tight, and just "persuaded" the linkpipe to the correct angle. Oh well... it all works out in the end. For the price I paid for it, it is a wonderful piece of kit, with some minor DIY caveat. If this is your first rodeo, I wouldn't recommend it. For those of us who have dinked with aftermarket exhaust plenty, it's no biggie.
As for power expectations... I don't much care if it a 2HP more here and 1HP less there. If I really wanted big HP, I would've kept the ZX14R.
I do like the fact that it is single sided and pannier friendly. For now, I've got the 14" can from the Delkevic slip-on I bought for my Street Triple R, just to see how it fits and sounds on the Ninja 1000. I've got a Delkevic 18" polished S.S. can earmarked for the Ninja 1000. I prefer to keep it quiet, plus I favor low-midrange torque vs. top end power. Delkevic quality is every bit the equal of the likes of Yoshi, Two Bro, and GPR. Akra/Remus/etc. are on another cloud deck... but so are their prices.