Different rear/ front mechs for a double and tripl



I have a Giant TCR2 that I have had for a couple of months now. Great bike, lovely to ride but the one reservation I had before I bought it was that it came with a triple chainring set ( Shimano 105 52,42,30 and a 12 - 25 cassette ). Its not too hilly where I live and my preference is for shorter faster rides as opposed to all day tours. I have not needed to use the 30 yet. I am only 35 and 160lbs and consider myself fairly fit so I am considering converting to a double ( 52, 39 ) and 13 - 23 cassette. A setup I have used over the last 20 years.
I have read many of the previous posts on the double v triple question and understand that I can simply replace my 30 and 42 rings with a 39 and change the rear cassette without any problem. However will the rear mech and also the front mech require changing ? I have read in some adverts that different mechs are available depending on wether or not you have a double or triple.
Opinions welcome.
Thanks in advance.

Keith, Formby, England.
That's strange. The TCR 2 that I bought came with double 53-39 and I have a cassette of
12-23. You will find it quite hard to set your own ratio unless you buy a complete cassette.
In my case, I want to have an 18,20 so that I can build a 12-20 and I have been told that Shimano doesn't sell them seperately....( what a ripoff !!). For the type of race I do , thats' what I need, but for the time being the original cassette is ok.
Now, to answer your question. I don't think you need mechanical changes. Maybe only a few adjustments. Better check with your bike shop
you can probably "get by" with changing (removing the 30, replacing the 42) the chainrings and cassette.

BUT, to do things right, and make it a true 18 speed bike, you will need to ...

1. change your bottom bracket to one with a shorter axle
2. change your front derailleur
3. change your left shifter/brake lever
4. change your crankset
5. going to a smaller rear cog (23 vs. 25) may mean
shortening the chain