Schorly, I am the friend to whom Raquel referred. I don't think you can go wrong with the Lamm L2. It is an outstanding preamp, and, based on my personal experience with my system, the L2 certainly pairs well with the CAT amps (JL-1 LEs in my case).
As for the relative strengths and weaknesses of the various former and current production model CAT amps, I would tell you that it is easy to find people who are willing to express opinions on the topic, but it is a rare find indeed to find an unconflicted party who has comparative listening experience with the CAT JL-1 LEs and the current production model JL-3 monoblocks. I have not had the good furtune to listen to these two amps in a comparative listening situation, and I have yet to find anyone other than Ken Stevens himself who has been fortunate enough to have this experience.
The JL-1 LE amps are said to contain very special, irreplaceable, hand-wound transformers that are critical to the performance of the amps. Whether this transformer and the other expensive parts in the JL-1 LEs resulted in an amp that is superior to the sound of the current production model JL-3s is a question few can objectively answer.