i just want to kjnow if there is really a huge diference?

 

I'll say it first.
What CAI since there are several?

 

mainly DOS, but since its so expensive... would i get simillar results w a filter in stock CAI?

 

Not sure, but I would expect the DOS CAI to be an improvement since the DOS doesn't pull air from the engine bay.

 

Stock airbox still always be the best in our case. You can replace the filter to a more free flowing one, but you have to weigh the risks with the oil'd filters clogging your MAF. The reason for the best performance with a stock airbox is it draws air from the front of the car, with plastic hoses that don't absorb as much heat as metal housings.

Remember, aluminum is good for dissipating heat, meaning getting rid of it, by absorbing it from its surroundings and getting cooled off by air passing over it(aka your radiator). An aluminum pipe or housing for a filter box with no heat reflecting treatments on it will absorb the heat in the engine bay and keep the ambient air inside of it warmer than with a plastic housing. Look up specific heat and compare the specific heat of a general ABS plastic vs aluminum. its about 1:2.

Having said all of this, I have an Alta intake housing with an AEM dryflow filter on it, with a ducted open scoop. I don't gain any performance with this, and if anything actually lose a bit of low end power, but gain a few (talking 1-2 whp) up top, when the turbo is out of breath anyways. I didn't do it for the performance "gain/loss" if you will, or "deltas", but instead I enjoy hearing the turbo spool and diverter valve "blowing off" when releasing the pressurized air back into the intake tract.

So, performance minded, go with the stock box, and maybe a free-er flowing filter (preferbly a dryflow since no oil will coat your MAF sensor [$400 replacement if you break it]). If you want the sound of the DV blowing off, then go with a generic cone filter (like a AEM dryflow) on a silicone elbow. You can hook just a filter up to the end of the MAF, however you may throw a code from the fluid flow characteristics (air=fluid).

Also, if you do a search on the forum, you'll find this topic discussed 100000000000000000000000000000000x times.

Good luck.