13 seer coil & 10 seer condenser

[superfanatico]

Ok so from the top I had a leak and called some guys out and they said it was my evap coil and it was an r22 system and a little small for my home so they wanted $$$$ to upgrade to a 13 seer 410A 3 ton system but I really didnt have the money so I called another place and they said they could just replace the coil and that the first guys just wanted my money so I agreed for $$$$ but after they finished my home didnt cool well still and my condenser started not turning on at times. So i called them back out and they said it was an issue with the txv valve and that they fixed it but again it didnt work right so I called them again and this time they said the outdoor unit was no good but again I didnt have the money to replace it and it did cool some so I just lived with it for the Summer. So here we are again and this time I got a friend of a friend to come and look as a favor and he said the outside unit seems to be fine then when he got in the attic he said they had the coil backwards and he would have to do some work to make sure they put the right expansion valve and that I was only getting a 10 degeree differential, but since they put the coil he thought they should fix it so I went back to them and they came out again and said the coil was universal and could go any way so that didnt matter and they said my outside unit was not starting some times. I had already done some research and told them that I thought it needed a hard start if they put a txv valve and they agreed on that part but said the problem was that with a 10 seer conenser and a 13 seer coil it was putting out all it could and the only way to fix it would be to replace the outside unit. He said he would make me a deal $$$$ for a new 3 ton unit that he has out at his shop. I called back the friend of a friend and he doesent think they can fix it with a 3 ton unit and suspects they didnt put the right expansion valve but thinks for that price they are trying to work with me and doesent know what to tell me to do because he couldnt match that price for me on a 3 ton unit. He said he doesent think they can even put on a 3 ton unit though because its a 2.5 ton coil and i have a 2.5 ton furnace. The only thing I have a part number for is the coil Trane - 4txcb031bc3hcaa and like I said a r22 2.5 ton condenser and I guess a 2.5 ton furnace and it looks like the issue is I am only getting a 10 degree differential but I dont know if the issue is with the mismatched parts and seer rating and the outside unit will have to be replaced or if this should work and the issue is just that they mismatched the expansion valve. So if anybody kindly took the time read all of that can you give me your thoughts should I be getting a better differential with what they did last time or with these parts is that the best I could get and require a new condenser?