Look at the lofts.  The AP2s have more loft than some irons.  it is a matter of perference as to what your lofts are on each club.  I went from CB695s to AP2s and lost some distance on the shorter irons because they have more loft.  The AP2s can be easily adjusted to the lofts of your previous clubs if you prefer stronger irons.

Also, look at the shafts.  the shafts can make more difference in ball flight and distance than the heads, which have other attributes such as feel and sweetspot which are more important.  Getting fitted for shafts would be a good idea.

Lastly, if your ball flight with the AP2s is acceptable to you, why not just get used to the new distances?  That might not work as you may prefer the old ball flight but it did for me.  I mentioned going from CB695s to AP2s above.  Well, I took the AP2s out of my bag because I was having problems with a stiff neck and wanted my old clubs in the bag while I worked through that.  My son claimed the AP2s.  I picked up a set of CB710s.  These also have more loft than the CB695s and I tried a different shaft.  The ball flight was higher and landed softer, especially the long irons.  I decided to give them a try and it has worked well.  I still have a bit of an issue with my PW and my 50 being very close together but I like the 54/58 combo so I may have to bend the PW a bit stronger to get it where I want it.  Overall, the clubs have turned out very good and I've got a different set of distances for each club now.  The key is to know what club you hit what distance and to have the ball flight you like. 

Get fitted.

--jerry

Alfredo,

Well to start with your X20 iron lofts are 2 degrees different to your new Titleist 5 and 6 are 1 degree different which should cause you too much difference but then 7,8.9 and PW is 33 and 35 titleist so that is 1/2 a club or 5 yards.  You should see the Ap1 ball fly higher than your X20's also.  Were you custom fitted for the Ap2s or did you buy of the rack?  If you were palying the uniflex shafts they are a sub 100 grm shaft and the standard Dynamic Gold shaft in your Ap2s are 120 ish grms which again could be lowering your swing speed a little and again reducing distance a little.

Hope this helps.

I am a 4 handicap and recently tried the AP2, I play MP 62's to get more forgiving club. I was keen on the AP2 as I play the Titleist 910 D2 driver and 910 Fd fairway wood. the ball flight is very high and I lost a great deal of distance and controll. The AP1's will perform the same way. the question is always... why change????

One of the reasons you may have lost distance is because the 6 iron is one degree stronger and from the 7-PW, the X20's were two degrees stronger.  You can bend your lofts one degree or even two degrees strong to match, just be aware that you will lose bounce one for one.  So if you bend your 7 iron from 35 to 33, your bounce will go from 4° to 2°.  What that means is if you are a digger, you may not have enough bounce on your clubs to keep the club from digging into the turf.  if you are a sweeper, it may be just fine.