Triathlon - 1st Tri-Bike -- HELP!

I normally post in the Clyde forum but need some Tri / TT specific info. A little help from the more experienced/knowledgable would be greatly appreciated.

I'm currently 5'10" 230# and dropping (thanks to cycling). I'm going to start doing TTs and Sprint Tris in the spring. I currently have a decent road bike ('06 Giant OCR Limited) but I'm looking for a suitable TT/Tri bike without breaking the bank. A friend of a friend is getting rid of his 2001 Cervelo P3 (Aluminum), Ultegra drivetrain. size 56(?) for <$600. I'm not concerned w/ doing minor repairs -- I expect to replace brake pads, tires, etc. Basically, I'm looking for an decent, affordable aeroframe / bike so I can start entering a few races and hopefully post a respectable time for an older fat guy. ( Yea, I know, It's the engine not the bike. )
From my research I've found that this model year did not have an integrated headset. Is that an issue?
Is the ride of an Aluminum frame as harsh as I've heard? (Current road bike is a carbon frame.)
Pros & cons of this Frame / bike ? Will a TT bike vs road bike make that much differnce over a 23 mile TT course? Does a steeper seat tube angle really help save the legs for the run??

Any other thoughts / insights would be greatly appreciated.

Thanks in Advance!!

It's a great pro-level bike. I'd buy it, no question. (Your only disappointment will be having a hard time finding it from the other Cervelos in transition.)

Don't worry about the headset. Everyone used to ride with threaded headsets. It's a non-issue.

Frame materials in of themselves do not determine the ride quality, the frame design does. Everything I've heard about the P3 has been good on ride quality. Also, tire pressure has a lot to do with harsh riding. Go with less if its a problem.

Elite racers have been shown to gain 2 minute riding the aerobars over road drops on a 40K TT. As you are not elite, the time savings will be even more (This statement is not intuitive, but it is true.)

There have been studies that show steeper angles do indeed save time running off the bike.

I'd make sure you do are to get fitted on your tri bike by a bike fitter with experience fitting triathletes (FIST certified is better.) This will cost you some money but will be worth it. Also, be sure to put in some serious miles on the tri at least 6-8 weeks before the race. It will use different muscles than your road bike and will take some getting use to. You also need to get where you can stay in the aero bars for pretty much the entire race so you can reap the benefits of your tir bike's design.

TT bike will make a difference. Seat tube angle will make a difference. Price is nice. Don't worry about the headset, on a tri bike that's waaaay down the list of things to care about.

Also, read the sticky on this topic: http://www.bikeforums.net/showthread.php?t=436387

Don't worry about the headset, on a tri bike that's waaaay down the list of things to care about.

There is absolutely no reason to change out the headset unless you want upgrade the fork or want a stem that is made for a threadless fork (which will also mean changing the fork.) The only other reason I can think of doing that is if you have a bar you want to install with an oversized diameter. In that case, there are threaded stem inserts you can get to hand those stems on a threaded system.

Thank you for your thoughts, advice and sharing your knowledge. I'm gonna pull the trigger & go for it.....

Thanks again!

Run Fast, Ride safe & Have Fun!!