If you look at your car and most others the fronts are always bigger.

They dont look stupidly big or anything. They just look powerful :)
 
You'l notice it alot if your running the 170 or a mapped 140 tdi. Not so much as standard though. imo its worth using for the longevity factor as it keeps your internals clean. But for power gains, best gains are noticed on tuned tdis.
 
Yeah the Optimax from Shell is best, petrol I noticed a difference compared to ESSO and BP's equivalent of super. The diesel equivalent is just as noticeable, as I've been in AndySpencer's beast when he was running both.

ED
 
Looks great matey, nice colour too! now i just need to find those headlights for mine! haha