Car is burning excessive oil, especially after sitting for some time (white/blue smoke) was told it needs valve seals. How much of a pain is this job? can it be done when the engine in the car? or does it have to be removed?

Some links from the MR2 pages. Not hard, just very time consuming. I'm probably going to do it when I do my timing belt in the spring/summer.

http://www.mr2oc.com/60-normally-aspirated...s-5sfe-car.html

http://www.mr2.com/forums/threads/88023-5S...l-(w-pics!)

If this oil is removable caps, it is not so difficult. Do not be afraid of this. For this operation, the engine need not be removed.
But it is important to find out what is causing the flow of oil and smoke from the pipe vyhlopnou
But it is better to begin with the oil glands of valves because it is less costly in financial terms.
I am sorry for my English.