Simota CBII is the same as Ingen, same idea, but cheaper ( it has no metal pipe to throttle body.
I think Ingen has an oiled filter, so you will need to clean it and spray new oil. this is the same as any K&N filter, or oiled aFe. With any oiled filters it is recommended to buy cleaner for electronics contacts, also sold as MAF cleaner ( look here for example
Link to MAF cleaner )
If you cannot find this spray where you live, I dont recommend you buy anything with an oiled filter. In that case you must select Dry filter. I hope Ingen sells one too.
For maximum sound and maybe the best performance in the perfect weather: Ingen, do not recommend Simota CBII, its too small of a solution ( just a filter)
For performance in hot weather and city traffic, people recommend closed box intake so that you dont breathe hot air. You are lucky to have 125i in Europe, your original airbox is already have the system that is alot like aFe Magnum Si
So if money is not important, in this order:
1) get a chip tune for your 125i to make it close to 130i power, cost will be close to $1000 ( no intake system will do this much horsepower)
2) buy complete BMW performance 125i/130i ($700), Simota for 130i ($750) (
Link Simota)
3) Cyba scoops for extra 2 horespower
If money is important but you want the best sound & to copy Simota for 130i,
1) Buy a filter from K&N Part# E-2022 ($50 , but only if you can find electronics cleaner), if you cant find cleaner, buy BMW performance Filter 13710445636 ( $100+) or AFe dry Part # 11-10111 ($70)
2) please cut:
http://www.babybmw.net/viewtopic.php...b0e4ea9fb977dc
3) Cyba scoops for extra 2 horespower
Just changing filter can be enough, and you should start here before you cut your air box.
Good luck. I am repeating my self too much
Believe me, I thought about every option possible and learned that there is not much difference except the price and how pretty it looks