The blocks are the same and the handling differences, if any, are determined by the option package/parts installed and have nothing to do with the steering wheel placement.
The turbos are different yes but there's tradeoffs. The Japanese spec turbos are CT20's with ceramic turbine wheels; while they're weaker and tend to fail when the boost is cranked way up, the turbine wheels themselves are slightly larger than the CT12B's found on the US spec 2JZ-GTE. So for max HP in the original housings the JDM turbos are better but they'll fail quickly. Using steel turbine wheels to rebuild them etc the Japanese spec turbos can make more HP than stock US spec turbos. But stock twins are a challenge to mess with and most folks replace all the parts that are different between the US spec and Japanese spec 2JZ-GTE.
You should do some reading on stock jdm vs stock usdm turbos, fuel systems, brakes, and b03b differential years. Otherwise, in terms of handling and block strength, they are literally the same car just different driving position.
For the most part, yes. The JDM Supras had a lot more option packages and different parts available. That's why there's so many JDM NA Supras (SZ model) that have no ABS, JDM TT (RZ model) that have small brakes and 16in wheels, etc. So getting a low optioned JDM Supra is typically inferior to most US spec Supras.
US cars were basically picking NA or TT, auto or manual, sport roof or hardtop, and picking a color. All US Supras had ABS, all US turbo cars had the bigger brakes and 17's and an LSD (the LSD became optional in the option list in US spec TT autos from 97-98 but I've never seen one that didn't have a factory LSD) etc etc.
Otherwise, yeah. JDM 2JZ-GTE's had somewhat less potent/long-lived turbos, smaller 440cc high imp injectors, a smaller intake cam, and a different ECU to match.
US 2JZ-GTE's had the CT12B turbos with steel turbine wheels, larger 550cc low imp injectors, a slightly bigger intake cam, and an ECU to match that included a MAFS instead of running MAP like a JDM ECU did.
Since most everyone changes the turbos, the fuel system, the cams, and the ECU; which engine you start with is largely irrelevant these days.