Cracked rods are very durable; they'll unlikely need resizing. The L36 rods on the other hand are very susceptible to OOR and will likely need resizing. Resizing is not cheap and the outcome is very dependant on the expertise of the machine shop doing the work.
Using the cracked rods will require L32/L67 pistons since the rod is shorter and the wrist pin is larger. If you're going into the bottom end I would check the mains for OOR. The L32 rods would be my choice because of the increased strength and them most likely not needing resized.
Also, make sure the font cover/gerotor and bypass is within spec. This will determine if the engine is getting the proper oil pressure.
Rebuilding the 3800 SII requires a little finesse in that the bottom end has very tight specs and the builder has to do his/her homework. If the block requires machine shop work be prepared to write a big check!..Worth every penny though. A correctly rebuilt 3800 is good for at least 100K miles.
