Some how I knew you would reply like that
You know, that just is not feasible to do that ... compare a kit with individually pricing items out. Now when you put together a special project like this, the outcome is always going to be the same ... a much higher price. Been there done that.
So your options are:
1) Buy the Tamiya kit and rob out of it what you need, sell the remainder as a static kit
2) Wait, shop around and get the electronics off eBay used or at a reduced price than from most sellers and vendors
3) Or just buy a tank WITH the electronics already installed
LOL
~ Jeff