You don't need such performing pieces.
- 2Gb is plenty for you, I suppose. 4Gb is not recognised because of the 32-bit OS that is limited in memory recognition.
- These processors will get somehow hot when they will be needed. Try to get something slower... they are too fast on what you are going to do. After all, they're laptop components, and such they are already low-consuming. A T5450 and slower would be all right, and you could always use the software RightMark CPU Clock Utility (if you run Windows) to lower the voltages on that CPU without any harm, as it will bring down both the heat (by at least 10C... tried it on my girlfriend's laptop) as well as the power comsumption. And you will have plenty of horsepower with a slower CPU, you dont really need a 4GHz cpu (being a dualcore)
- Install a slipstreamed version of Windows XP on your FDM done by yourself (or else it's illegal). The FDM disk will already reduce your load/write times by ALOT, it's going to be even better if you can have a slipstreamed version and you will shut down processes during boot.
Other than that, seems okay for a nice'n'fast Carputer. Your current specs are quite overkill, so I would suggest dropping them. I dont know about the other pieces, since Im new myself bout this Carputer thing...
A 45nm process on a faster CPU will keep a bigger strain in heat, as everytime you will need the CPU it will run it at full speed, and these speeds will generate more heat than a slower CPU on a 65nm process.