Iceage made their sled 398 lbs with really a tunnel and a rear skid, spindals and possibly a-arms. I would bet that a Polaris production sled off the Rush bulkhead in 155 RMK form comes in around the 435 lb mark bone stock.
Here are some pictures of the bulkhead assembly:
The sections are assembled with bolts and a Bonding adhesive that is simple to use. Say you hit a tree and damage the left front section of the bulkhead. In the past this meant a complete service chassis from the factory. Now you can simply remove the bolts, heat the affected area to a around 300* and remove the bad section. Clean all surfaces with common cleaning agents, install the new piece with the bonding agent, install bolts and thats it, bulkhead is repaired.
The other side benefit here is the lack of distortion the chassis will go through during the assembly process. The factories will have less twisting of the frame as they assemble the sled and engine alignment and clutch alignment should vary less from sled to sled.
And finally all this is LIGHTER and CHEAPER than the old bulkhead assembly. Can you say lucky us?
All the large pieces in the picture, 3, 7, 13, 14 have a suggested list of $315 TOTAL!