Triathlon - Road bike to tri conversion

I have always ridden road bikes in triathlons as I ride mainly road and only do a few tris a year, and cannot really afford to buy a tri bike. Alot of my friends keep telling me I should get a tri bike and touting how much faster I will be. I have been playing with the idea of getting a forward seatpost, and changing out the bars to aero and pursuit bars on my extra road bike. My question is..how much of a difference will this make?

Good idea. That will make a pretty significant difference in terms of your speed--you'll be farther "forward" on the bike, which will allow you to get lower and more aerodynamic, and allow you to "save" your muscles on the run (though some people don't find that this happens as much).

The only drawback of going to a forward seatpost and pursuit bars on a road bike is that the handling will be very twitchy. Basically, both wheels will be too far "backward", and this results in a funky weight distribution with too much weight on the front wheel. Triathlon bikes are designed to overcome this, by pushing the rear wheel forward and having a shallow head tube angle + fork with more trail.

However, in my opinion, this loss of handling is a reasonable sacrifice to make IF you ride on easy courses with few long downhills, and you're on a budget.

Thanks. Ill give it a shot. If it does not work out well, then I can swap back to the traditional stuff pretty easily.