I have always ran 10W-30W Raw oil in my engine and changed the oil every 3,000 miles. I started a new job where Im driving alot more, and having to change my oill about once every month and a half. I am considering going to Synthetic just for the fact I don't have to change the oil as often. Now I just read ppl usually go about 5k and change there filter, and 10k cahnge oil and filter. How do you change your filter with out leaking alot of oil with all the oil still in the block, or does the pan contian most of it. And you just top it off when the new filter is applied? And it looks like most ppl run Amsoil, do I have to use a diff oil filter with syn.? or can I use the OEM toyota ones? And can you buy Amsoil local, or in bulk since I do my own changes.