In 100 bu corn a 1660/1666/2166 would be plenty of combine for an 8 row head.

In 200 bu corn the same combine will work fine you just won't set any speed records.

A 1660 has a theoretical capacity (figuring 100% efficient) somewhere around 1300 or so bu/hr in 15% moisture corn. In 100 bu corn you would be traveling 5.36 mph to put that much corn in it.

Not saying you should buy a 1660/1666/2166 but if the right machine at the right price came along it would do the job just fine. But if a 1680 would definitely do better in the 200 bu corn.

Looks like $40,000-$50,000 would get you into a nice 1680 or 1688.

A 883 or 983 head could be bought for $5000-$7000 and have every wear part on it replaced for another $4000 +or- so figure $10,000 would have a good head.

$20,000 would get a late model "field ready" 1083 easily.

If you can do your own wrenching $5000/yr will replace a lot of parts.