Based on the data provided, we can observe that the average auction price of this coin in past auctions has been 171.48 euros. Additionally, the condition of the coin in this auction is 90 (EBC).

Considering that the coin will be auctioned in the upcoming days with a starting price of 160 euros, we can estimate a maximum purchase price based on the average auction price and the condition of the coin. Given the high condition (90), it is likely that the final auction price will approach or even exceed the average auction price.

Therefore, an estimated maximum purchase price for this coin in the next auction could be around 180-190 euros, considering the trend of previous prices and the condition of the coin. It is important to note that in auctions, the final price may vary depending on demand and other factors, so it is advisable to pay attention to the auction to adjust the offer accordingly.