To add to this debate about the need to remove the TB when cleaning it, I had the same opinion of "if you're going to do something do it right with no shortcuts".
So being a bit unsure I contacted my SEAT dealer (workshop manager, really helpfull guy in the past - saved me a fortune on many occassions), and asked him if I remove my TB to clean it and replace the gasket, will you re-align the TB for me?
He responded with, "no need, you just turn the igintion to position 1, press the accelerator down and this will allow you to clean the otherside of the TB."
You can clean the pipe side without the accelerator pressed. Well this is what I did and this has removed the flat spots in the acceleration (1500-2000)rpm.
My cupra now runs so smooth it is fantastic, as I had already replace the N75 valve last month with only a slight improvment.
Cheep fix for an annoying issue, well done Cupra.net....
Cheers.
Rob..