Dear Kalan,
Happend to read responces to your question and want to give you my opinion (if it is important one?!).
I owned four different CAT preamps: from Reference to Ultimate. Had a chance to hear most of the preamps on the market in my system, or in the systems I know very well(sorry, didn't have Holand pre at home) and nothing could make me to sell my CAT, only if the new model was coming, and own one now.
Tell you why. I agree with Musicluvr and Jamsoul about neutrality of this product. Only,it comes together with the warm, full sound, huge soundstage, and the best bass you can get from the tube preamp. Never sounded up-front. Single instruments and voices are like you would hear them in a real life. Phono stage is "forte" of the CAT and, possibly, best available outside some external mega-buck components. I played this preamp with many different cartriges and amps and never had problems with matching. Did I get lucky?
I just remembered one old review on CAT preamp (possibly Dick Olsher?) where he mentioned that ...if you don't like something about your system after you introdused SL-1, look for the answers somewhere else. Chances are that it showed you what you didn't hear before and will help you to tune your system...
About your problem with "in-your-face" sound. Think about placement of the speakers (new component allways comes with their re-positioning), cables you use, etc. By the way, using cables like Magnan Signature will help to reduce gain. My freind use two of them and it helped in his case. Also, CAT used to have available "special" volume control for the customers with very small rooms or high gain components to give them twice more steps before it gets loud. Missing resistors are for the phono loading and will change the sound of the cartrige,not gain. You should use them with low output MC. 100 Ohm or lower will give you warmer and deaper sound, 150 Ohm and higher would open it up.
Don't give up on your CAT before you CAN'T use it at all. I know people who sold their CAT for various reasons and now regret they did it. After all, it plays music!
Good luck in your difficult search for the PERFECT preamp in your system.