Hi and welcome.
I'm with BB on this one. Changing to HID may be cool for you, but the reality is, you'll likely just annoy and frustrate other drivers around you for little gain.
As for the lowering and wheels...definitely find some nice wheels first, then think about the lowering kit. 35mm is a lot, on a people mover. It may rub, it may not, but new wheels will make a bigger difference to the overall look than a lowering kit, in my opinion.
Personally, I'm a fan of the Touran. With nice wheels on, I don't think they need lowering.
Good luck with your decisions and hope you like the varied and sometimes quite conflicting opinions of us Vaskers.
Cheers, JC