Well this post might sound stupid to most, and perhaps it is, but I was wondering if i have set up my boost controller for 1 bar and I did this over winter when it was VERY cold, will the pressure drop now that we go to warm times? I could see a drop on my HKS EVC boost controller, and no boost leaks or anything else, just turned up the dial to 2% more boost and now I am back to the before values...I guess is all up to how does the density of the air affect pressure/volume

That's quite correct, most boost controllers work on a 'ratio' or percentage system and 1 bar in the winter may be 0.9 bar or so in the summer.

Some like the AVC-R, work to a boost level and will adjust the duty so 1 bar is always 1 bar.

Joe