Like its been said the mr muscle mod is just a temp thing,the only way round your problem is new or recon turbo,as i said i had the exact same problem
whistling and lots of power when on boost,diagnosed as cracked and sticking viens so had no choice but replace it with a new 1 total cost inc...
well we have just been to see the new q2 and my god its nasty,the interior is like something out of the 80`s,dont know what they were thinking in the design
of the car,loads of angles on the exterior and the new grill like all the other new audi`s is terrible can`t se them selling lots of...
yes both high/low beams are h7`s i used the philips 130`s in both beams and they were very good a lot better than the oem`s, good luck in changing the bulbs without taking the bumper off,might be possible if you have child like hands.
if you have someone comming over with vcds i would wait and see what they say,how old is the battery,you said regular diesel is that supermarket crap,my money is on glow plugs they are about £25 a piece have a look at europarts
sounds like glow plugs, a bit more info might help service history,mileage,what fuel are you running it on??????? have you it scanned to see what the problem could be,could be something like a sensor or something a bit more serious