Assuming you have an M103 (what year 88-91 US spec 300SE), you don't need any special tools. You might not have the socket you need for the head bolts, a 12mm doube hex or something like that, but it's something many cars use these days. I got a a set of double hex bits from Pep Boys for ~$10 and it has the size of bits I need for the 300SE (12mm) and 300SDL (10mm). The bits fit into a 1/2" hex socket. About 2" of bit sticks out of the socket and that's enough. I see special tool catalogs with 6-8" of bit. Such tools might make a personal statement but I don't see how they'd be necessary in an M103.
As long as you can clean the bolts and they aren't stretched, you should be able to reuse them. My head bolts were 3mm shorter than allowable so I imagine they can stretch quite a bit and still be okay. I think the more relevant issue will be the condition of the threads. I'd replace the head bolts with corossion and/or pitting in the threads that can't be cleaned away. Don't forget to tap the block threads and clean the holes thoroughly before refitting the head.
I haven't heard a lot about M103 cylinder head cracks but I wouldn't leave it to chance with a visual inspection. Have a shop do it while the head is out. Besides, you probably want to have the valve guides checked while the head is out.