To estimate a maximum purchase price for the coin in question, we can analyze the provided data:

1. Current Condition: The coin has a condition rating of 80 (MBC+), indicating that it is in relatively good shape, although it is not the best possible condition.

2. Starting Price: The starting price is 1600 euros, which serves as a baseline for the auction.

3. Price History:
- The average hammer price in previous auctions is 2559.25 euros.
- Hammer prices in past auctions for coins with similar conditions (80-90) have varied, but there are examples of auctions that have reached up to 8000 euros in exceptional conditions.

4. Price Trends:
- In recent auctions, hammer prices for coins with a condition of 80 have been around 1700 to 2400 euros.
- The last auction with a condition of 85 had a hammer price of 2200 euros, suggesting that the market is willing to pay higher prices for coins in good condition.

5. Estimation: Given that the coin's condition is 80 and considering the price history, a reasonable maximum purchase price could be in the range of 2200 to 2500 euros, taking into account that the average hammer price is 2559.25 euros and that the condition is an important factor.

Therefore, an estimated maximum purchase price for this coin could be 2400 euros.