I used these and they worked perfect. Probably the same ones. http://www.amazon.com/Precision-Brand-Micro-Miniature-Stainless/dp/B001HWGMBG?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00
Just check your voltage in the dash without turning the car on before you flash if you're a little worried. You can just put the car in ACC mode and check the voltage of your battery. If it's 12 or above you'll be fine.
You only need to replace the check valve that is between the can and IM(intake manifold). The other one that is between the can and intake will never see boost so it's pointless to change that one unless you just want matching check valves.
IMO it's safe. I've sold and bought via Paypal plenty of times from private sellers and companies. Never had an issue that went unresolved or resulted in me losing money.
You just mentioned it bud....PayPal...They almost always side with the buyer if something goes wrong. Just make sure you don't gift the money and make them send an invoice that is specific. Such as Cobb Accessport V3 for Ford Mustang Ecoboost (Unmarried/Uninstalled).
The Motul Xcess only comes in 5w-40 as does Rotella T6. But Motul does make other lines of oil that come in 5w-30, not sure if anyone has run anything other than the Xcess.
I love the Magnaflow Comp. Once it's broken in you don't get much drone cruising at highway speeds. I have mine for sale though if anyone is interested. I haven't had a chance to post it in the classifieds as it's still on my car at the moment, but it is all over facebook on just about all of...
Check Walmart for the Pennzoil Ultra Platinum. I run it in my DD(Altima) I pick up the 5 quart jug there for $27. It's a good oil I saw about an extra MPG when I switched from Mobil 1 EP when it first came out. But I run the Motul Xcess in the Stang until I feel the need to switch to something else.