the order of doign things isn't overly that critical, UNTIL you start playing with internals
if you do rods, you'll do your overboring, any crank modifications (if any), and your pistons all at once, to save tearing the thing down again.
You'll probably modify the oil pump too.
And you'd be advised to do your head work at the same time, although this is perhaps not as critical...
new valve body will tighten up your shifts, header/mid pipe will provide more horse power - both increase the fun factor... i say, flip a coin.
i'm gonna be doing a lot of drag and dyno after i get my header/HFCatMidpipe just to see where i am then go from there
i ran a 17.9 at the track with the stock tranny and only a CAI and CBE... i'm hoping the valve body will shorten my time because of the shifting... i want the rods cause i know i'll be redlining or even more(boom02)... im also going to go halfsies on slicks cuz my bro wants some too... so yea...