My two cent advice:
I don't know about other bikes, but with Suzuki, specifically the SV1K, there are two ignition curves, one for gears first through third, and one for fourth through fifth. From the reading on all of the SV sites, Suzuki does this so that newbies don't acidental loop the bike, with a over aggressive throttle hand. The TRE I have makes it so that the bike is always usuing the latter to the two curves I mentioned above.
It doesn't make the bike any more power, top HP is still the same, but it does change how fast the power comes on. The SV650 guys say they don't notice a difference.
With the 1K, I definately feel a big difference. Only issue is cold start ups take a little longer.
advice over.