Need advice: comparing two 320is

I am evaluating two 320i's and looking for an educated opinion.

A 77 with 98K miles in very good shape - on little rust patch, very nice interior and fine mechanically. toolkit, 1.8 ltr. 4 cylinder auto. Seller is asking $3600.

The other is an '83 Alpina - 5spd., nearly perfect inside and out. Lots of goodies. Sunroof, tool kit, etc. 120K miles and owner is asking $5500.

How do these cars sound in terms of pricing? Which would you go for?

Thanks!