TheHowl...

I just got off the phone to Allianz the warranty guys...

I was right, if you have the top level cover, i.e. the one that covers you like a new car warranty to the value of purchase, you are allowed to mod and it doesn't completely void your warranty.

Just that modded part isn't covered and anything that could be caused by that modded part.... like changing springs then the struts fail, that wouldn't be covered as an example.
Its exactly the same as a new car warranty.

If you don't have the unlimited cover anyway I'd flush it down the toilet as the limits imposed on each part are a joke.