I saw a little while ago a billet s488/96/1.32, the gt4718 has I believe a 93mm turbine? The 4718 was my original choice, but I got this turbonetics for cheaper than a box stock 4718.
It definitely would be easier to stay compound rather than go triple.
Pm 02Bigstrokin his name is Josh. He can tell you from experience the differences. He used that turbo with both turbines before in a twin with a 366 as a high pressure.