Gas Station real estate future

[Eden Rock]

Hello All,

I am interested in buying an old tear down gas station, with intent to redevelop as a new gas station and a small smoke shop etc. The lot is 1/2 acre but quite busy intersection hard corner  

I would appreciate if anyone can help me with my questions. 
1-is it worth investing in this kind of project? , since a lot of gas stations are closing down. 
2-How much would tear down will cost 2500sf building? considering removing underground tanks as well. 

3-Should we remove existing building before starting to look for construction loan? Or get approved and then remove the existing structure.