You can mod in whatever order you want, but if you add on like a 3" exhaust it will really free up the power when you turn up the boost. Its all about airflow and all of those mods will help in different ways, and some will help even more in conjunction with other mods. Which is why they are put in a certain order... its for a reason. Hahn knows what he's doing, however it is just a suggestion. You should read up on turbo's and if your going to mod your car it is a good idea to know your engine pretty well... so research can only help. Have gone over to www.dsmtuners.com or www.dsmtrader.com?

Im not trying to point you away from this site, but this site is mainly for the 420a motor and its possible that you can find more help/suggestions on this subject on a site that is based around the 4g63.