One thing: Do you really need to change the air filter? What is the standard and severe replacement in the owner's manual? Are you following it or are replacing it prematurely just on a whim? If you don't have the book, plz visit this page where we had a lot of discussion on standard maintenance intervals. You'll find your desired info there.
Buying any replacement part from dealers is 3 to 4 times expensive. NBK (it is the one which comes factory-fitted) brake pads for Cultus you'd buy from dealer for 6775/- will be available for 1750/- in the market. If you do the maths 1200/350=3.42 which falls b/w 3 & 4. Therefor the genuine filter if available in market should cost you around 400 rupees.
One more thing is to weigh the filter on a scale. The heavier the filter, the greater its price. Reason being actual mass is greater (mass=kg, the amount of matter put in it by the manufacturer is greater). The heaviest filter will be most expensive, assuming all cost same to manufacture (i.e. tools and labour cost is same and only raw material cost is greater).
Now maybe the OEM filter provides same efficiency as Guard, but greater pick-up (less restrictive). So in effect, filtration efficiency will be same and airflow would be different. If you buy Guard, (hypothetically assuming that since Guard is cheap, therefore it is inferior) you'll save the money but you have to pay the cost somewhere: you'll pay it in terms of driving pleasure. OTOH the premium commanded by OEM will provide you the same driving pleasure. The other difference may be longevity. Under continuous suction, filter element may tear up. Now if one filter is more resilient it would have more life. As you know, paper (card) is more rigid than cotton. May be that is the advantage of OEM over Guard? How do I know? It would be better if you had posted some photos of the products.
Let's come to the Rs. 190/- air filter that your shopkeeper tells you as 'best'. I highly doubt it will be best. I mean it may be decent and perfectly OK for your application, but if it is too good to be true, then most probably it is. (Likewise it is not sensible to buy the highest priced item, it may not be the best). Does it have a brand name and model number? Why don't you post it here along with photos. Just by telling 'a Rs. 190 air filter' wouldn't spark anything in anybody's mind. About this air-tight packing I understand that it is in a plastic bag for shipping?
The polyurethane foam filters previously talked about must have il sprayed on them for proper function. OTOH, new filter always provides less than optimum filtration because it is very dry. Once you have used the filter somewhat, the blow-by return system deposits oil fumes on the filter and filtration becomes better. This is one of the reasons why premature air filter change could actually harm your engine. You can always oil your standard air filter even if it didn't come oiled in the packing. You can use any oil or there are some oils available in the market for exactly that purpose. Filters that are oiled from the factory are an accepted concept and it definitely helps filtration efficiency, but it is not the sole factor. If a filter is oiled but has a lousy filtration media it may provide less filtration efficiency than one with better element but no oil.
Not offended at all, because your post shows you actually have done some homework instead of being lazy and just asking, leeching others' knowledge. What I would advise you is to use each filter for once, and then come up with your results like this and this. (As you can see, this is no rigorous quality analysis, but this is the best we can do). Considering Cultus EFI is newer and not much is known about it, lots of people will have questions. Why not you be the one who provides answers? After, pakwheels is not only about asking questions; it is about finding solutions mutually as well.
For the time being, plz post the model number of Guard filter you saw. If I went to the parts shop in a few days, I'll see if I find anything suitable for you. This suitability will solely be on the basis of visual inspection, not any rigorous engineering analysis.
