Wow, thats extremely impressive. You've managed to capture the Gothic details very well, especially on the exterior. The signature of Gothic architecture is an emphisis on the vertical and you definatly captured that here. I'm pretty sure that you have basically every part and detail of a gothic structure here. I can tell you know quite a bit about gothic architecture. I'm guessing you were goinng for a Rayonnant Gothic style here? circa 1230-1250 CE. German I'd say by the tracery towers.
(though the tracery tower influence did spread to the Iberian area- Barcelona Cathedral has one- but its Facade and over-all layout is quite a bit different from what you have going on here).
From what I've seen you have some pretty creative part usuage going on which is cool. Its also very impressive that you managed to make every window stained glass. In the cathedral I built I had to leave my windows open ><.
I think my favorite part here is the tracery towers. very good use of those technic wheels.