I've used 5w-20 on my modulars for years. If you run 5w-30 its not going to hurt it though. Honestly I don't know why ppl even have an issue with this but it is what it is. I get a 5 qt jug of full synthetic Super Tech 5w-20 at wal mart for $17.99, another quart for $3.99 and then a WIX filter at Napa for $5.
I honestly think people get way too bent out of shape with oil to the point of spending $10/qt on the uber high end stuff and "magical teats of jesus" filters. Even the cheapest autozone conventional oil has to meet certain standards and as long as you don't run an orange fram death can you will be fine if you keep up on maintenance and don't go too long between intervals depending on whether you are running conventional or syn.
2000 Mustang GT Steeda #0048 34k miles. 99 Cobra 4V swapped, FTBR IRS swapped, exhaust, tuned by James Gordon.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.