Nice work dude.
Mufflers looks really great and the head is coming along well.

Just a few questions though,
-havent tried resin before, so is the resin easy to use and non toxic or is mixing it a pain and it needs a lot of open ventilation and safety gear??
-what is the full brand that you use?
-it looks like you have casted resin on top of an original head and then carved back the shape that you want, is that correct? just curious to know if there is a particular reason (pros) to doing it that way compared to just sculpting with epoxy/putty etc. on top?