3" pipes are obnoxiously loud - I love 'em, but exhaust drone will undoubtedly be unbearable in a van. 2.5" seems to be a wise choice here. The Flowtechs you have picked out rank nicely against other performance brands on a
Dyno-Test, and seem like a good pick. Flowmasters ranked pretty high as well, and not only do they have great performance, but if you get the stainless variety they come with a
Lifetime Warranty. I hope it all goes well for ya, and keep us posted! Cotton