Phase1 or phase 2. Or custom, it all means different things to different people and different tuning companies so you can't categorise every tuning method.
stage 1 is generally perceived to be the best option for a standard car and further mods require further tuning options, we offer 2 options for turbo petrols, stage 1 for standard cars and custom mapping for anything after that and then REVO of course has its own upgrade path.
The reason power is tailed off at 6500 rpm is due to the fact the power curve has plateu'd at this point and the KO3 tends not to enjoy high rpm as it simply can't move the volume of air associated with high rpm, especially with intake temps on the standard intercooler and the restriction posed by the standard intake. EGT's are within acceptable levels even held on the dyno under high load, however dyno testing EGT's isn't ideal as they never replicate on road EGT testing, but as a rule if it's safe on the dyno it generally will never see the same level of load in real world conditions, I have logged literally hundreds of cars on the road and the dyno for EGT's and held under load over 5 runs on the dyno the peak EGT's are usually 20% higher that any replicated road car, on road test.
The power achieved is extremely safe on the standard down pipe, an aftermarket down pipe would be a benefit but not essential for this level of mapping, after all we are only talking a few % more power over and above what Giac and Revo can achieve with a stage 1 map.