Robot Clones
So... as you know, Starscream's been working hard on a way to get himself a new robot body, as well as a workaround for his current issue of "if I die, I lose my body and don't get ported back in, I'm just stuck and forced to borrow someone else's skin, and that sucks." He's finally figured out a way to do that which will probably not offend the Porter too much. I'm treating this as a power upgrade, so think of it what you will.
Starscream will be creating a partially techno-organic body which looks, on the surface, completely human. It will appear to breathe, sleep, and it can eat, and yes, before you ask, it's functional in other ways. The only obvious cues that it's not human are a few plugs in the base of the spine, the chest area, the upper thighs, and the forearms; and these are easily hidden. Other than that, it doesn't smell human (not like motor oil, just that he smells too clean; characters with super-scent powers will REALLY notice), and obviously anyone with X-ray vision or who bothers to check his pulse will notice that oh wait, not a human at all. He'll also probably give off a faint uncanny valley feeling - ie, he looks too perfect, not enough skin blemishes and the like. Finally, animals will now hate him on principle because he smells and sounds not-right.
The robot will have all of Starscream's current powers - null rays, lasers, and supersonic flight. It will be modified to allow him to survive flying his top safe speed, and will let him withstand G-forces that most humans can't. Other than that, it is certainly not any more durable than a human body. A punch to the gut will damage vital components; getting blasted with fire will kill the organic components and probably break a lot of the inorganic components; getting frozen in ice will do much the same. He might still function after that kind of damage, but it won't be pretty (think Terminator, with the whole rotting-flesh-hanging-off-a-metal-skeleton thing). Choking him IS possible, as this cuts off his breathing - actually a cooling system designed to keep his internal components from overheating. Cutting that off will cause him to overheat and shut down, so anyone wanting to necklift him still can.
TL;DR - he won't be that much more durable than a normal human.
The body does have self-repair systems, and these work at about the same way that a human's natural healing does. If he breaks an arm, it'll heal at the same rate as a human's broken arm does. I have no idea if supernatural healing will help this; the answer is probably a resounding no; however, he can be opened up and worked on by an engineer to fix things to speed up the process.
The body can deal with food, and even has a sense of smell and taste - it does, however, require more power and nutrients than a normal human body. Starscream will have to plug into a wall every night to keep powered up, or else synthesize his own energon. He can survive off of food alone, but won't be able to generate enough power to run his flight engines or his null rays. In order to ensure that his body can self-repair properly, he's going to need to supplement this with a steady diet of silicon, gold, copper, iron, titanium, and a few other, weirder elements necessary for forming Cybertronium; as well as energon (in that case, electricity won't suffice). Basically, he'll be much more high maintenance as a robot than as a human.
Using his powers will cause transformations - for the null rays, guns pop out of his forearms; for flight, his heels transform into engines (and yes, he's going to have to figure out a workaround for how to wear shoes with this), as will his hands (Iron-Man style stabilizers). This'll be a bit like Alice in the movie - ie, CREEPY AS HELL when it happens. It'll also make his eyes glow much brighter than normal when he's about to use one of his powers.
Now. How does this relate to death? Starscream will, at all times, try to have two available. They cost a few million dollars to make, but he feels this is well worth it. Upon dying, Starscream just has to posess one of them and it'll come online. There is, however, a significant drawback - initially these are inanimate objects, ie, "just robots", with no programming or anything. As such, for the first week of possession, the bodies will not move right, sound right, or work right. He won't be able to use his powers, won't be able to speak like a normal human (we're talking MASSIVE flange for the first three days - like, Soundwave levels of NOT TALKING LIKE A HUMAN BEING), and, in short, won't be able to go out in public at all. This is twice as long as the normal death penalty turnaround (three days, I think?). The reason for this is that when a spark is introduced into an inanimate object, it very slowly begins to convert the circuitry in an item to living circuitry - kind of like if you put a soul into a pile of meat and said meat suddenly started to grow nerves. Starscream also won't be able to feel properly for that first week - everything will be numb. He'll get alters like "YOU ARE IN PAIN! :D" but won't actually FEEL it as pain, which will cause him more harm than good (pain exists for a reason).
At the end of the first week, he'll have enough living circuitry to be able to behave like a normal human, but it'll take a month for his body to fully stabilize and integrate itself with his spark. During that time he may simply glitch a little - speak with flange occasionally, have his powers go off without warning, etc. His magic also won't work for the first week: he'll need time to re-adjust to a new body.
Starscream won't be able to just bodyjump when he makes the first one - he actually has a huge problem with simply offing himself. He wants to live, and even if he knows that he can survive dying, he doesn't like to. Thus, he'll need someone to kill him to make the first leap.
Being a robot will give him a few other advantages. Slipstream won't be able to hear his thoughts as long as he's in a robot body. What other telepaths can do will depend on the telepath - if they can't read robots, then he's immune. HOWEVER... technopaths can fuck with him any way they please. Starscream has deliberately NOT installed a wireless connection into his body, and while there is a fiber optic cable connection at the base of his neck just in case, he'll probably never use it. He KNOWS people like Tony Stark and GLaDOS exist, and he doesn't want to get hacked. If they can get into his systems without an internet connection, however, he is probably fucked - his firewalls may be good, but not THAT good. He doesn't have technopathy at all, any connection to the internet he can get will simply key off his normal abilities as a hacker.