Engine: I'd look into a 1UZ (vvti, of course), as it's an aluminum block that is somewhere between 60-80 lbs lighter than a GE, and it comes with 300 hp/300 ft-lbs stock. So, you get more power, drop weight, and improve weight distribution. Plus, you get a nice NA powerband. (Ignore this if it doesn't meet the requirements)
Trans: Have you looked into the AR-5? The v160s/v161s are obviously very strong, but I've heard that they can be clunky/noisy. I wouldn't opt for r-154 unless the ratios worked best for your goals.
2003 GGP | "You Can't See Me"
Hotchkis sway bars, LS400 bbk, Stance coilovers, Customwerks rear strut tower bar & trunk brace, Megan diff. brace & traction bars, OBX short-tube headers, Fidanza exhaust cam gear, GTE cams, NX wet kit, winter camo wrap 👀