I have a 2010 FLHX with 2 in 1 Reinhart 3" slip on. I want to change this to 4"....

Should I keep 2 in 1 setup?
Should I go with 2 in 2 setup?
Should I go True Duals?

Not sure what to do here... I wanted to go True Duals but I don't like the pipe running through the middle of the bike creating more heat... I live in Florida.

 

2 in 2 sound better to me.

 

The pipe running underneath the bike produces minimal heat...and that's mainly why it's under there...you don't feel it!
The stock 2-1-2 setup is actually very efficient. You'll get the best results with good mufflers and a proper ECU map or whatever fuel managment you're running.

Good luck

 

NEW 2009-2012 Touring Rinehart Xtreme True Duals Chrome w/ CHROME END CAPS 4 Inch Mufflers Dual O2 Ports.