200tdi rebuild help

Hi Guys, Sorry if this has been asked before...I'm going to shortly be rebuilding what was a 92 200tdi 130Defender which was an absolute pile.
Anyway the last big investment is a galv chassis but was wondering if I should get a 300tdi chassis and engine/Is it worth it, will it be a straight swap/Willl everything else fit?
I need it for carrying heavy loads and the current engine had a nervous breakdown when I last showed it a hill...Also want to fit hydraulics which seems a mission with the lt77 box.
Sorry again,This is all quite new to me and I want to get it right the first time.
Cheers
Rob

Is it worth rebuilding if you need a chassis and an engine??

only if one of the seats is in reasonable nick

No probably not but I need a chassis to store all those spare parts on...