I noticed that the front and rear bumper beams are made of steel (Heavy). Is this for body stiffness ??? I noticed on other vehicles that they are aluminum extrusions or egg crate design. I think they could saved a lot of weight on both ends.
I'm sure they are steel to also pass our 15mph crash tests as well. More of a safety feature for the engine, radiator, etc. Either way, I still think the steel beams are better for HUMAN safety than aluminum (butter) beams.
The JDM front bumper is actually smaller, and lighter than the USDM version. The change was for USDM regulations. Keep in mind - despite the performance Subaru is still very concerned about their safety image.
Me? I'd run the JDM beam if weight were a concern, but I would be sure to have a beam of one kind or another in there. If you're all that concerned about weight just take out your AC system.
Steel was chosen because it was cheap and effective. They didn't want the STi to end up in the $40k range so all the tricks couldn't be thrown at it. Plus this way we all have something to tinker with! I've been intending to fabricate a titanium rear bumper for the best strength - weight ratio but haven't gotten around to it...
You mentioned removing the A/C. What would be the weight savings ?? I think everything is aluminum ... condenser, plumming ... etc. The compressor would be the only thing that would be of any savings. Maybe 5-10 lbs ???
There is 40-55 lbs to be lost through the AC system but keep in mind you then have no ac and no defroster without heat. I would like to fabricate one myself and offer it to the community but fear of lawsuits from ppl getting hurt after install have kept me at bay.
You said fabricate. What would you need to do but to remove it ??? replace the compressor pulley with an idle pulley ??? I thought all you would need to do is get a smaller belt. I am interested in removing the system. I never use the A/C anyways. Just worry about resale. Not many people would buy the car without it. I Guess I could reinstall it.
Maybe we should be talking about this on another forum