A what?

really, your ECU is tuned from the factory, there's little or nothing to gain from changing the management unless you do heavy modding such as F/I, change in compression or major head/bottom end work. I also have never heard of a "redline ecu" but would put my money on it being of paperweight use to a prelude and possibly any car

I have no comment on the ATTS other than it does have power limits and will disengage in multiple error situations, other than that all I know is most people who ask about modding SH's heavily are told to sell and buy a base or something else