Its more so that they are the only ones that don't loose power... They will give perhaps a little more throttle response (and a lot more noise)
The only issue with the KTR kit is that its sucking in hot air from the engine bay... Then both the V6 and maxogen, its all about getting it positioned to get cold air into it, often people having to remove the battery and relocate to the boot, or putting in a smaller battery..
All 3 have there ups and downs, I don't think its worth it on a normal car (as in not tracking etc). I had the KTR kit on my old 197 and removed it after a week.