Today I have reconsidered my budget and decided not to buy those expensive polar clothes and sleeping bag since, as it seems, the forecast for February indicates that temperatures won't be extremely cold.

Indeed, these equipments are really made for extra cold temperatures, from -40°C and above. Therefore, they might be to warm for me to feel comfortable and avoid sweating. 

The budget is now set to 4200€.

A big THANK YOU to all those who supported me so far.