I've had the Cp-E and Tial BOV and now I run the ER and tial Bov. From the charge pipe alone there really is no power added. If you run methanol then the larger diamater piping can help in atomization though.
Most people who upgrade the charge pipe plan on going the methanol route but you dont necessarily have to go methanol to upgrade.
If you dont want a BOV you can always add a forge DV option or turbosmart DV options to replace your factory DV and keep the stock charge pipe or you can buy a charge pipe that utilizes factory style DV options.
All of this is really a matter of preference or goals with the equipment.
I like the ER charge pipe because of how it mounts just like factory. They also mount their meth nozzles in the right location unlike some other charge pipes.