I suppose a little DEEK-PSYC-101 would be beneficial so you understand my master-plan.
I would rather spend a couple bucks more right now on parts that may not necessarily be... necessary... until I get the head-work done. To elaborate I'd rather buy the header/uppipe combo now than spend $300+ on the Grimmspeed service (including flex pipe & coating) and then in the near future, say early 2013 when tax season hits, negating that investment to eventually buy the header/uppipe combo I'll need. After dealing with the core charge and all the shipping, it'll probably damn near even out anyways... Then I need to sell it off too? Gah!
Simply put... I'd prefer to do everything for the big build (to me) now, then when the extra couple grand I'll need for head-work is available it's a simple process of tearing it down, messing only with the heads, putting it back together and getting it retuned. Not having to go through the part selection process over again and having to find buyers for my used stuff. I realize that I'll be a bit bottle-necked in the meantime, but it's just how I work I suppose.
Redundant explanation is a bit redundant, I know.
Bill Gates said something something "I'll always chose a lazy person to do a difficult job, because he'll find an easy way to do it." In this instance... to me anyways... this means avoiding redundant work, and in the long run avoiding creating more work for myself trying to part this stuff out when the time comes.
...redundant.
EDIT: I should have a price list from my usual vendor here shortly for the parts I submitted. Things are getting closer and the sheet as it sits is within my current allotted budget. Who is "DP" that you named in the sheet?