With money being an issue at the moment, any luck with either of these?

http://store.summitracing.com/partde...5&autoview=sku


http://store.summitracing.com/partde...5&autoview=sku

2003 Ford F150 4X4 w/ 5.4L

If these will get me by, what's the advantages/disadvantages of the different size pipe? I know bigger will flow more, but for day to day driving is what I'm looking for.

Thanks for your time!!!!