I would ask Q2W before I buy one of these I think he has one and if I remember right they are pretty heavy???
Also the zilla has the largest diameter axle out there at 50mm so you won't get any beefier than stock unless you go to a JJ&A drag axle.
For the money I'd go with either a set of the LTR 450 with either .25 or .375 spacers (you can buy from Druablue for $20) or the Gforce which can be bought for around $110 unless you really want an aftermarket axle.
I just think there is many more places you could spend $300 bucks on performance.