Guy wants to make an offer outside of court...?

I have a feeling the guy I was gonna go to court over ended up getting served the papers today because he called me. Its over a lemon car. I bought a car for $4300 and I've put $2000 in repairs and it still has problems. I know he's scared because there could be criminal charges as well. He wants to settle for $2000 for the repairs ( not including the tows ) and wants me to take my car to his mechanic to have a diagnostic done, he said his mechanic because they can make payments that way. Should I do this or am I taking a risk having his mechanic do work on it. I told him If I do this Id want to see ASE certification, the diagnotic paperwork stating what is wrong and if its longer than a day fix I'll need a rental car because this isn't my fault. I tried making arrangements prior when my motor gave out and he had DC the first time which was 3 months ago. The suit was a little over $5000 and can be up to $6 in CA. Also he wants to give me $1500 cash and then a $500 IOU. He's telling me If I go to court since he doesn't have a job they'd have to do a payment plan as well. Is this true? What do you guys think???? Im not trying to milk anyone I just want what is right. I just want the car that I was told I purchased not the junk it ended up being a day after purchase. Suggestions, ideas? Experiences?