depending on where you live, a custom surecam or a wade cam would be a better bet than crow - they can grind you a cam bigger than crow do for less money, and tailor the cam to suit your needs. if you decide to get a proper big cam then a chip would be benificial, as well as head porting...but decide if you are going to go to that extent BEFORE you get the cam - get the head done, then give the cam place the flow figures and they will do up a cam to suit it - it will go heaps better than the other way around.
3.9 diff gears and LSD (you would need a correction box to make the speedo and auto work properly) extractors of your choice (pacemaker race series, JMM or wildcat?) seem to be pretty good. quickcorty has pacemaker i believe (14.6 quarter) - but JMM are good too IMHO - and a 2.5" mandrel bent system with two straight through mufflers.
thermo fans from a EF are good to gain a few kW from, as are a pod and some kind of cold air induction setup..there are a million billion threads on here about what people have done...
you can ditch your spare tyre, jack etc, which might gain a little as well, but best of all its free.
try source some 225/65/15 brigestone G3s that are worn and put them on steelies for the back, they stick great if you get them nice and hot at the strip :s6:
I would also consider buying an EA Falcon S if i found a good one. What did a standard EA run on the quater with a 3.9 Multi Point engine? How much could i expect to pay for a good EA? It would have to have the Multi Point engine. My old man had an EA for 7 years and the only thing that went wrong with it was he had to replace the radiator once.
EAs are lighter, it's true. They are also a damn sight cheaper. I usually wouldn't expect to see an auto EA crack $2k in W.A., a manual might go as high as $3500 if it was shmick. No XRs in the EA range, and usually you won't see people try to ask for more for an S-pak as they are not really very special. Only difference is badging, MINOR suspension, and interior trim, really.
I would encourage you to go this way, any part up to ED will bolt straight in with a very few exceptions, and many of the EF/AU bits will fit easily as well.
Personally the driveline is your biggest holdup, IMO if you leave it auto you are wasting your money. That 4speeed box will never push you to those times without spending vast amounts of money on either huge KW or the box itself....mush better to go to the 5speed I reckon.