Howdy! I inherited a coworker's '05 Prius as my company car late last year. It had 264,000 miles on it that were all highway driving. It has been a great little car for what I need...43 mpg and plenty of "zip" going down the road. About 2 months ago, it started using oil. It has now worked its way up to using a quart every 900 miles or so. I drive 250 highway miles per day on average, so it goes through it quickly. Had my local hybrid-certified shop look it over today. No leaks anywhere, but the plugs are discolored and there is pretty significant soot build-up in the muffler. Looks like it's losing its rings and burning oil...bummer. The Prius has 297,000 miles on the clock right now. My mechanic can get an engine with 47,000 miles on it...price tag is $3500 installed. Everything on the car is in good shape...body is awesome, interior decent, brakes & tires are good, exhaust is solid, steering components are tight, HID headlights were replaced in December...the only thing I know it will need in the next year is rear shocks. Is it worth taking the gamble and fixing it, or are there several other major failures coming just around the bend (i.e. tranny, batteries, etc)? Neither my mechanic or the local Toyota dealer have ever seen a Prius with that many miles on the clock, so they couldn't recommend one way or the other. On a side note...what additive (Lucas, etc) would work best to nurse it along until my employer decides what to do? I don't want to put in anything too heavy, but even a slight slow-down on the burning would be better than nothing at this point. Thanks!