tri bike fit, part 2

Yesterday, I did my tri bike fit - part 2. The session consisted of riding a predefined course (short time trial) in at least 2 slightly different positions to identify "the sweet spot" of highest efficiency and power output. Goal was to ride both time trials similar in terms of cadence and heart rate in order to compare times and wattage.
The overall distances and measures of my position on the bike were identical except for the seat angle. I completed both trials in almost identical time without major differences in power output or heart rate. The 78 degree seat angle position seems slightly more aggressive by feel but not necessarily less comfortable. In reality the position would be more aerodynamic, hence "faster". Based on the assessment, it was concluded that I can ride at 77-78 degree angle to start with - say for the next 1 or 2 season. A more aggressive position might be possible down the road... Once I have my final numbers in terms of sizing, dimensions etc. I can go bike shopping.
It looks like I should buy a model that accommodates my riding style and height, ideally a frame with 78 degree angle or the appropriate adjustment flexibility to achieve at least 78 degrees.
I test rode a Felt DA which I liked but having nothing to compare to (yet), it did not tell much.
Based on my potential sources for bikes, I will be looking into following bikes:
Argon 18 E-112
Specialized Transition
Trek Speed Concept
Cervelo P3
Felt is still an option but the bikes seem to be priced at a premium compared to some of the other models (except the Trek Speed Concept).
I am hoping for a deal on a 2010 model... budget is an important factor in the equation... at least for me.