it's the lengths of the pipes coming out of the block, the uneven length in the factory ones give the rumble. since these are "equal length" supposedly it will sound like any other 4 cylinder turbo.
-10 seems a bit excessive, I wouldn't worry about the flow difference between the two much at all.
And front of radiator will be fine on your setup since it'll sit so far back from the front of the bumper anyway
Finally got the gromet thing on the firewall that the steering rack goes through in! had to take the column out but wasn't too much of a hassle since the dash is out
Don't mean to sound rude,
but if you have to ask, then you probably shouldn't attempt. Unless you have a lot of money and time to spend on this then there isn't too much point when most nissans make a perfectly good drift platform and there are so many aftermarket parts available specifically for drifting
it can be done but it isn't easy and things will break
2 cents