360ci

I haven't had any problems changing to synthetic oils. I've been running Amsoil products in all my vehicles for the near part of a decade. I change the oil once a year and for $15 mid year I send a 1/4oz sample out for analysis and it tells me I don't have to change it for another year on top of the 6/7 months I already drove on it. My work SUV has always ate a bit of oil, about half a quart every 3000miles, and now with running synthetic I only need to add a quart every 7000miles, so consumption has dropped slightly; and it tows 4-6K every weekend.

If you like changing the oil regularly, I'd stick with the non synthetic stuff. I changed reg oil in my old 2.5L I4 3speed Dodge Spirit every 2500miles and the engine still ran strong with over 260K on it. If the frame didn't rot through I'm sure it'd still be running now. I find you can go farther with your money using synthetic oil due to the increased drain intervals. I know a few folks who still change it every 3-4K, but it's a waste of money then. What brand or grade you want to use ultimately comes down to personal preference.

Quaker State is a good oil, but here they want almost $5 for a quart of QS 5W30 non-synthetic! For double the price I can get Amsoil Synthetic and drive 20K/yr on it. Best part is that it's still golden brown at 9K of driving, where as reg oil turns black on me at the 3K mark in all my vehicles.

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'99 Taurus 3.0L 2V Vulcan 145hp; 124,250m
'00 Durango R/T 360ci 300hp (modded); 112,800m
'06 Pontiac G6 GT 3.5L 220hp; 21,100m

Amsoil in all vehicles!