I'd say spend the bucks. I highly doubt you'd be able to wear out the bottom end, unless you absolutely neglect the engine. Bottom end is likely good for 400K+ miles.
Replace the drip tube connectors while you're in there, and make sure the drip tube passages are clear.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.