temp sensor for so high temperatures....
must recomend what the industry uses... Thermocouples
They are a bit expensive and need expensive amplifiers if they are to be relied upon within a degree or so, but they can handle exhaust temps. http://www.analog.com/static/imported-files/data_sheets/AD623.pdf could mabye be used in amplifying the signal if doing it a bit more cheaply.
pressure sensors... www.omega.com (range from cheap to VERY pricy)
David