Difference between D and XP?

[TheGoat]

I'm building a 3600 watt system with a cap. I have a d3400 under the hood. I want to get 2 more for the trunk. Which will work better the D or XP?

[Nathan @ XSpower]

If you are not going to be competing, then I would suggest the XP. Less expensive and if you aren't putting it on a meter you will never know the difference.