The Magic 2, Apple, & Messiah are ALL "Great" chips...
If you do buy a pre-modded PS2.....Make sure you get one of these chips in it....
As you stated, you are DEFINATELY better off getting a pre-modded one...The soldering of these chips is extremely difficult...
Go with the Pioneer A03, A04, or A05 (will be released this week)... They are the -R format you mentioned and have been the PROVEN winners in the PS2 backup scene (Except for the A05 since its not out yet)...
I would definately rec. using Primo DVD to backup your PS2 dvd based games...
Also something you may consider, is purchasing (if you don't have one) a 100% Clone CD compatible burner...
You should use a seperate burner for CD based PS2 games...
Well..This should get you going in the right direction...