OBX is a cheap brand so thier stuff isn't that great, thats why they don't fit right.

It shouldn't be hard to find a prelude in a salvage yard, thats probably where you will get the best deal for the arm rest. But, there is a guy on ebay parting out a 5th gen as we speak.

As for the strut bar, I guess you gotta send it back if it doesn't fit.