It think the 1.6 Vitara engines are around 80 and 90 bhp for the 8v and 16v versions.
I'm not a fan of bigger engines in SJ's and run the standard 1.3 in all mine, my belief is that the more you modify the more you have to modify
If you're going to upgrade a 410 which is around 45bhp then be aware that bigger engines can be very heavy and completely change the ability of the vehicle.
Plus if you start putting serious power through a drivetrain designed for 45 bhp (especially offroad) then things are going to break.
I know a guy with a V8 Samurai diesel which puts out well over 200bhp and HUGE torque, he's spent ages trying to get it right.
its broken transfer boxes/props/axles/hubs you name it and now is basically sitting on Toyota running gear/transfer box/props/axles etc and has had to have the chassis strengthened and braced so its basically only a Samurai body thats left.
Doesn't feel like a Suzuki to drive it now and its definitely not as agile or as able offroad anymore.
So although it definitely sounds good its not something I would go into light hearted, there is major work ahead if you go down that road
I've never done it personally but I don't think the 1.6 Vitara would be too difficult or too severe a conversion to go for