if your asking about someone cutting your wires then matching them up to the right ones and saudering them together? you can do it yourself it took me 20min. for the engine harness and the interior ecu harness. not worth spending that much. if you want later i can post up what wires go to which one if you're putting this into a 240sx.
i believe it might be illegal for you to put an s13 blacktop into an s14 chassis if you have the same smog laws as idaho. You might want to check that out before you do this swap. you either have to have the same year engine as the car or newer. definitely check this out it can be a big fine.
in Missouri any car '95 and older is emissions exempt, so it would be fine,
but the car I was buying was sold before I could get out to look at it.
oh well theres bound to be a 240 floating around ready for a swap.
when i did my emissions here in idaho they asked what engine was sitting in there because i forgot to hook up the aiv and i told them so i talked to the head of the air quality board and i guess here in idaho it's not illegal to do swaps as long as the engine you are putting in isn't older than the car due to smog laws here. so they just wrote up a letter for me so i'm exempt from the visual and they just do a sniff test. if i were to convert to obd2 then they said i have to let them know that way when i go to get emissions done they will test as obd2. it's pretty laid back here.