My old (But freakin' awesome) french road bike goes fast, considering that the only times im racing is pretty much against my friends who all have mountain bikes. Needless to say I always win. But I would like even faster speed. I understand that IM the engine, and I need to be fit, but would upgrading to a newer and lighter road bike gain me any noticeable improvements in speed?
The question is "would upgrading to a newer and lighter road bike gain me any noticeable improvements in speed?".
The answer is a loud YES!!
The doubt remains regarding "is it worth the extra money?" and that's difficult to answer. If you have a lot of money, or really want extra performance (for a given fitness level) and don't mind throwing the money, you'll most probably get back this money in the form of a lighter, faster bike.
But I have to say: sometimes one spends a lot more money and get back not so much extra speed.
(of course I'm talking of AVERAGE speed during dozens of miles, not isolated bursts of maximum speed).
What I think you should do, before anything else, is to FIND OUT A GROUP OF ROAD RIDERS to go along. I understand you want more speed, and you won't get the challenge from a MTB group, if you ride a road bike.
With a group of roadies, you'll not only find out how it is to ride along a faster pack, but also will see a lot of different road bikes. Most probably you'll notice that not always the faster rides have the lighter or more expensive bikes.
Hope this helps!