Izotope time stretching algorithm

With the computing power of todays computers a key lock that has little to no artifacts must be possible, the current one whistles and squeaks the mids and highs and warbles the kicks, this is the broken part of the software and is just not usable. This is present as soon as you turn on key lock or at even slight 1 bpm change. I am exclusively techno using harmonic mixing and have to mix tracks with the exact bpm this is very limiting for what i can mix in my collection not being able to use key lock with tracks of with even the slightest bpm difference. I don't know how open format djs mixing different genres live with this sound quality degradation of the current software. Is Traktors underlying audio engine to blame too? I feel Traktor lacks in the mid lows and is slightly boosted in the mid highs giving an overall less warm sound???, this combined with the elastique 3 algorithm does this also contribute to those artifacts. I understand totally that its down to the quality of my files, my collection is all Beatport mp3s so they should be fine at even a 1 or 2 bpm difference.