Not necessarily.
I know how everyone on here bangs on about how performance filters are smaller than the standard panel on the omega...some are some aren't.
I have a K&N filter cone, (not for an omega incidentally, but adapted to fit) which has a small inverted filter section inside the top of the cone too, the area of the filter is 525.4cm2. The standard panel filter has an area of 505cm2. Add to that that the paper used in the standard filter is more flow resistant than the cotton fibre in the K&N and the K&N (a big enough one at least) will definately allow more flow.
However, as has also been mentioned if you are then just sucking in a load of hot air, you will reduce, not increase the performance as the air will be less dense and therefore offer less oxygen.
So it is very important if you do change to a cone filter, you make sure that it is placed in a way that provides cold fresh air to it.
Also the oil used in the K&N has been know to damage the MAF sensors on the omega, so oiling sparingly is very important.
Its easy to work out the area of your cone filter versus the standard one. The standard one is approx 505cm2.