what would be the typical cost that one should expect for going K04 if it were to be done at a shop?
To get the performance out of a K04 or the mentioned 2867R properly preparing the engine would include the following parts list to get rid of all the intake and exhausts choke points, insure proper ignition and provide for best air cooling.
Parts
1350 - K04 kit
900 - K04 tune (Off the shelf tune with a loader so you can put tune on yourself)
250 - Neuspeed High Flow discharge pipe
190 - Neuspeed High Flow charge pipe
1200 - 3in Turboback exhaust
600 - Unitronic Intercooler
50 - NGK plugs
125 - Fresh set of ignition coils
300 - High flow intake
350 - Motor/Trans and pendulum upgrade
5165 - Parts total ( Of course you may have some of these parts so actual amount you might spend will be less by that amount)
1200 - Labor
6365 - Total
It would be more expensive to go GTX2867R because it costs more. CTS sells GTX2867R kit for 3299.00 (vs 1350 for the K04). It flows a lot more than a K04. To really take advantage of it (500whp or more) you have to build the motor and increase fueling and do custom tuning. Then you are up to
around 12-15K. I have built both K04 and EFR7163 setups.
To me the best value for street performance was my K04 setup. It was also plenty of power to have fun on track days. You can get to around 340-350 with a K04. I think with a GTX on stock fueling you are probably going to be able to hit 380-390whp. I personally would just go K04 and give up the extra 40-50whp and keep the money difference for other mods..... like brakes.
Just an opinion -