1. NO NO NO, do not ask for 2 units instead of 3! That's totally missing the point and will come off as non-committal. "Hi Mr. Professor, thank you sooo much for hosting me, spending your lab money on me, and your precious time and energy on me. By the way, I don't think I can meet you all the way. Can you let me back off a little bit? I need two instead of three units, because, come to think of it, you're really not that important to me after all and I have better things to do." You are an undergrad. And you are NEW. He is a PI. You should be doing everything you can to impress him and learn as much as you can.
2. Yes, asking for a project that is "lab techniques for research" totally misses the point. First of all, research means studying a project or concept, such as "cell signaling in mice brains" or "glia cells and their influence on neurotransmitter release in nearby neurons." The point of doing research at all is to learn more about a concept that nobody knows about. It's about discovering new things. Therefore, a project is not studying a project. An independent research project means that you will be given a specific question the lab is trying to answer. For example, if my lab studies quails (let's be general, for the sake of illustration), your project might be to study quail wings and their aerodynamic properties. The relationship between undergrad-PI (or whoever your mentor is) is a mentorship position. That means the PI/mentor, who is smart and has a PhD and knows what he's doing, imparts his scientific abilities to you by guiding you through the process and supporting you in your research. You are an apprentice as much as an intern in their field of study, meaning "biology" or "ecology," and not "general techniques of laboratory science." those general techniques are acquired as part of the research study.
So, do NOT ask for a "research techniques" project. The reason why you're supposed to learn about how things work in the lab right now is because you need to know the waters before you can navigate them (i.e. understand the field better before you can study an unanswered question). The reason why your PI doesn't want you to start now is because every lab has its timeline and schedule, just as every project you do has its own timeline. Let's say you had class X and class X had 3 projects assigned to you, one due week 5 (project A), another week 7 (project B), another week 9 (project C). If your friend jumped in week 4 and said, "I want to work on project B with you! please? I'm so very interested!" you might tell your friend "wait until week 6, after I'm done with project A. Then I can accomodate you." I don't know exactly what your PI has going on, but this is an illustration. Until then, learn as much as you can, appear as attentive and hard working and thrilled by the research as you can (even if you're not yet, pretend you're thrilled so that when you really do fall in love with the stuff, you'll have more momentum going for you. We all start somewhere).
To answer the original question: I took 2 units of research credit for 3 quarters, and I'm starting a 4 unit independent research thing right now. I love research! It's so much fun. It's an intellectual challenge, you never know what coming next, and you get to wrap your brain around unknown concepts and questions and it's like a cool game. It keeps you on your toes. You're both afraid things won't work out at times, and also excited hoping things do... looking forward to learning more about the puzzle and putting all your hours of studying to good use. And, ultimately, maybe even glean some clinical insights into a disease. At the undergrad level, it's nice because you can learn in a "safe zone" - no thesis deadlines or graduation pressures to meet - just have fun learning the ropes and trying things out, and if you mess up, you're just an undergrad and no one is really counting.
Hope that helps. Best of luck.
