Against a mech 
IG list probably with russes and manticores? Well to say the least I think it would be difficult. So as stated earlier, a bit will have to be reshuffled to account for the lootas and tankbustas actual cost. I probably would not go with the tankbustas as they aren't that good a busting tanks 

 . Plus with the glory hogs syndrome your opponent can pretty much control what they will be doing from turn 1 with so many vehicles on the field. I would make a suggestion like dropping the tankbustas and getting 2 deffkoptas with 
TL rokkits and a buzzsaw. But I guess you want to keep everything on the ground (hmph, dakkajet...). I would probably go for a massive screen of gretchin to run in front of the boys. With so many the 
KFF will have limited effect, if you lost that and got a weirdboy, you guys could either be blasting across the battlefield or meltagunning a tank. So you could loose the 
KFF mek, take a warphead, still 85pts. Then drop the tankbustas and get 30 gretchin. Maybe even loose the dakkajet and get another 30... that's a tide alright. But the jet would probably come in handy so maybe just stick to the tankbustas.