You will notice more performance at night comming into winter due to the colder dencer air...
This is common for any car... Cause if the air is 10 degres cooler entering the air filter its gonna be 10 degres cooler at the throttle body (allow for some variance of course)...
This in turn will make the turbo sound different and improve performance... But i have seen boost increase under stock control or with a bleed valve....
Us with electronic boost controllers dont see these things happen anymore...