Yup, like I said, the only guys who think they are weak are fullsize GM guys. There is a Jeep in our club, it has a 468, TH400, D300, D60F, 14FFR 44"TSLs. This thing can blow all 4 tires on basically any surface... he isnt worried about his D300 breaking. There is another guy, has a Scrambler, 360, auto (whatever the Jeep auto is called), D300, D44s on 36" TSLs... wasnt worried in the least about his D300.
I dunno, its prolly a personal thing, and I imagine there are a lot of busted up 300s around, but there are also ways to break a 205 if you try hard enough.
That being said, you HAVE to replace the input and output shafts. Add in the adapter, then if you want the 3:1 kit, you are into it for quite a bit of $$.
Mike