Triathlon - What to know when buying my first triathlon bike

So, I'm very serious about switching from a road bike to a triathlon bike, and I have a number of questions before I empty my wallet. For reference, I'm currently riding a Specialized Tarmac Expert and intend to purchase a Argon 18 E-114. Let's ignore price in this thread, as if I'm going to buy one, I'm going to do it right, without ever desiring an upgrade/getting jealous ;-).

Also, I have only done one triathlon (NYC Tri - Olympic distance), but intend to do many more -- mostly Olympic, maybe a 1/2 Ironman, too. Probably 5 tris/year. More importantly, though, I love to ride, and I love to do it FAST. I'm a fitness buff. I typically go on 60 mile rides and emphasize speed, and occasionally top out at 100miles through hills/mountains (9W to Bear Mountain, for anyone that knows NYC/NJ).

So, the questions:

1) Does it make sense for a rider as I described myself, to go from road to tri bike?

2) Will I see a considerable speed increase?

3) Generally speaking, will I find it MORE or LESS comfortable using aerobars? My back needs to be stretched for about 10 seconds every 10 or so miles on my roadbike. Will leaning on aerobars lessen or further this discomfort (and by extension, if the answer is "further," will my muscles get used to it?).

4) What key things do I need to know about riding a tri bike? What can I expect to lose from the road bike and gain with the tri bike?

5) Do people on tri bikes ever climb standing up? I don't think I've ever seen someone doing that during my training rides... I know aero is key, but I also know perceived exertion on steep hills is lower when standing. What's the deal with that?

6) Will a tri bike help my legs out a lot in going into a run? The first 2.5 miles kill my legs during brics/tris.

7) Anything else you feel like filling me in on???

Thanks a lot for the help, guys!

1. yes it does but keep the road bike for off-season training/bike races. (unless you need the money)
2. depends on your definition of considerable. will it make you go pro... no. will it add a mile or two per hour.. yes. the longer the distance the more the time benefit.
3. generally less comfortable, the position is more forward and you will have to bend your neck at a slightly higher angle.
4. you will lose some power that you have on a road bike. Certain muscles are used more on a tri bike than a road bike and certain muscles used less. On a road bike, it is an optimal balance, on a tri bike it balances so your run muscles are saved. You will gain massive aerodynamics (assuming you couple it with a skinsuit, aerohelmet, aero wheels, moving the bottle behind your seat and for a guy on the high budget these things should be also on your list)
5. Yes people stand, but usually tri courses are not very hilly. I have seen people try climbing at 9 mi/h in the aero position... I think they are weird.
6. Yes the bike will definitely help your legs going into the run. training bricks more does too.
7. I don't know if you are completely set on the argon-18, which i can see is a great bike, but if you do not have the additional buget for race wheels, consider something like the Cervelo P2 (just remember that it won the bike at kona once) or a last year P3 and some HED 3s or other race wheels. if you do, then buy whatever kind of bike you want. Also nothing kills the aerodynamic advantage like loose clothing. if you invest in a $3000 bike with $2000 race wheels all that advantage will be killed by a nice cotton T-Shirt, but you seem serious and probably already know this.

I hope that helps, if you need any clarification or elaboration i would be happy to respond.

Edit: As a rule of thumb the aero position does not benefit unless you are going at least 20 mi/h.

I currently only have a "tri" bike and ride similar to you, minus the hills being in South Florida. Recently I have found that I want to ride more in pace lines and my bike is not conducive to this. Yes I ride on the horns but can only do so for about 1/2 hour before it becomes uncomfortable and I will move to the front to take the lead and stretch out in the aero position. I did not see that on your list but it should be considered if you ride in a group.

Long rides in the aero position are not a problem, I do 60 to 100 all the time without a problem with having to stretch out. Again, flat roads with the occasional hill (bridge) thrown in.

Yes people riding aero up a hill does look VERY strange and why they sacrifice the power to ride that way boggles my mind. Yes the aero position will be faster on the downhill, just remember that it will not be as stable as a standard road bike. That is if your descents are technical.

My opinion is to have both an aero and a traditional bike (trying to figure out which to buy at this time myself). With both frames you will be able to ride on a hillier course, route and with groups.

Obviously you currently have a road bike, yes? I find actually find my tri bike much more comfortable than my road bike. The longer the better. I know I've got a fit issue with my road bike as after about 20 miles my hands go numb and by mile 30 they're so numb I have a hard time shifting. I've never experienced anything like that on my tri-bike. A little stiff in the neck the first 2 or 3 weeks but that's come around too.
For me the negative of a tri-bike is the group riding aspect, but I'm going to be testing that out a little (staying off the aeros of course) this weekend. Handling is different but you get used to it pretty quick.
Climbing is not really much different. I've been really training trying to climb sitting down but I really don't have many challenging hills around here. A couple 8-9% hills but they're only 1/4 mile or so. Shifting is a little different, but again you get used to going to the shifters from the horns even when standing.
I say go with a Triathlon bike and let things fly! I really don't think you'll regret it. Most roadies just look at them with wonder and don't understand them. Put your miles on it and you can handle it as well as most 'b' group riders handle their road bikes. If it's a hammerfest with sprints and breaks stick with your road bike.
Good luck!
--Sax