The coolness factor of the Sturmtiger and the quality of the work you have done will go far in making your battles more interesting. I have been up against IFA tanks before and the key on both sides is team work. an IFA tank by itself is easy pickings for a coordnated attack by as few as 2 tanks (just like any other TBU equipped tank) but if its flanks are protected by team mates (or the landscape) it could really turn the tide.