Spoke to tuner, he said that the nature of the HKS boost controllers is that they hold the wastegate closed until the target boost is reached and then the boost controller starts controlling the boost. In other words, the car while boosting up is relying on the car's natural boosting ability and hence this is why is it slow.
The new HKS EVC can make the boost faster by adjusting the gain/offset at a particular RPM, so I might try that. Ill increase the gain at 2000rpm and see what it does there. There are 5 RPM points that can be set, what would be best if my redline is 6800RPM? Tuner has set the 5 points at 3000,4000,5000,6000,7500, but should I set it to 2000,3000,4000,5000,6000 rpm?
Also the spikes in cold weather and low gears are probably due to the load on the engine. I was informed to set the gain to 95% and see whether this minimises the spikes. Ill give this a go too.
Explanation of dyno graph from tuner below: