Can I remove this emission piece on S-5?
 

Just picked up a J spec S-5 turbo engine. I am going through it and removing the emission equipment. Read the FAQs, but I wasn't sure about this part. It looks like it basically plumbs coolant through the t.b. along with a "soleniod" on the back of the upper intake. I want to make this car/motor as simple as possible. I dont have to smog it. Also I plan on using all my S-4 turbo wiring, computer, afm etc. I bought the engine after i bought all the conversion pieces. So if that makes any difference. My gut feeling is to remove it and plug the coolant line.
Thanks for the help.

Sounds like you are talking about the BAC valve and the coolant line on it.

The BAC valve boosts RPM at idle and very low speed when the engine is under load (for example the air condition is on, or the power steering, etc).

The coolant line to the throttle body is simply a line to a cold idle boost (until the coolant is at normal operating temps) the throttle is held open slightly so the engine does not stall when cold.

Removal of either will result in a loose of driveability when cold and at idle. Other than that you can remove them if you are in a state that does not require the emissions system to be intact.