[KennyP]

What is your end goal? Do you want to get serius with adding power and tuning, or just want some extra kick from the engine?

If you just want some exta power then any stage 1 tune would do.
Dinan was im guesssing one of the first tunes you could get when this engine was brand new. Now that N54 is 14 year old engine design there are alot of options to choose from. I would not choose something thats only 1 map... set it and forget it type of deal... and would get something that is a full tuning system... different maps for different hardware mods, upgrade path etc.

With cobb i have many maps and an upgrade path to follow if i wish. Used to have 3 different stage 1 maps...
stage 1 drive 95 fuel ( mild)
stage 1 sport 95 fuel ( sporty)
stage 1 agressive 98 fuel only ( agressive)

Now with updated maps i have only 2 variants: stage 1 95 and stage 1 98 map. Of course i still have older maps i can use but new ones are ok and i used most aggressive map previously anyway.

When i get tired of stage 1... and i already am graving for more power. You have new maps ready to go. Add intercooler and chargepipe and you can chage your map to stage1+ FMIC. Its advertised + 30hp.
Swap out to catless down pipes and you can switch to stage 2 maps. thats extra 50hp. Do both and you can run Stage2+ FMIC maps.

Big plus for me is that i can install and uninstall any time i want to. For example when i give my car ot a family member i put it back to stock.
I can data log , monitor gauges, read codes. All this stuff is useful.

And i actually got my Cobb V3 used from ebay UK a lot cheaper than it retails.

Cobb does not work with your car because they are up to 2013 or 2014 Z4 35i for some wierd reason. But there are similar tuners out there that offer upgrade paths and are as a matter of fact newer and better.

MHD is the first one to come in mind. They have also nice upgrade path set up for you and so on. Lot of information available aswell. 4 years ago MHD wasnt as big as it is now. Now if i didnt already have my Cobb accessport i would surely go MHD. Maybe someday i will throw Cobb up for sale on ebay and grab MHD. Probably when i get more serious with building my car up.

On dual cone air filters... I think for stage 1 maps they are not necessary. If you start changing hardware on your car like downpipes and intercoolers then dual cone intakes have an effect. Debris i would not worry about. Also heatsoak does not matter either as air is heated up by turbos anyway and then cooled by the intercooler. Quality of the intake filter is what matters. I would only buy BMS DCI. I saw some other brand dual cone intakes on youtube and the filters started to deteriorate and break apart. Burger motorsport DCI is very popular and havent heard any horror stories, only good things. Also if you are going full bolton inlets(pipes from airfilter to turbo also help turbos breathe better and actually give some gains.
Outlets from turbos to intercooler seem not to do much and are not worth it.

For DCT i have read that some have been able to install M3 GTS software or something on it. Personally i dont see the need for modding it. If DCT starts to slip at bigger power levels there are upgraded clutchpacks you can buy. SSP and DODSON... Not cheap though.