Mitsubishi Repair: using oil, eclipse spyder, engine seals

Question
I have a '97 eclipse spyder, 5 speed, 120,000 miles, that is using oil, 1 quart per 400 miles. No leaks and no smoke... we changed the valve seals and the pcv valve with no luck. Any suggestions?  

Answer
Anna,
Going through 1 qt every 400 miles is a significant amount of oil.  If you are positive it is not seeping out and not burning off, its possible it seeping into the cooling system and contaminating your coolant.  I would recommend having a mechanic do a leak-down test on your engine to see if there other engine seals that are leaking.  They can also add a dye to the crankcase to help detect where the oil is going.
Good luck!