First - wider tires do not help - they actually aggravate the situation. We're not dealing with low slung, performance cars here - a wider tire puts more rubber on the road and gives you better handling by reducing side slip - do that with a vehicle with a high COG and you will increase the probability of it rolling over, raising the COG higher, increases that probability. If you want to compensate for raising the COG, it is the "track" (the L-R spacing between the wheels) that needs to be widened, not the tires.
Let's now take a look at your buddy's Vitara - super springy and leans bad in corners - you don't provide a whole lot of information so I'm going to have to make some assumptions - let's start with my understanding of super springy - bouncy - perhaps like a bouncy castle at a child's birthday party.
If we assume he was using stock springs with spacers, the spring rate would not have changed, so for it to be described as super springy, the problem was mostly like worn or poorly chosen shocks & struts - springs support the vehicle's weight and there is always a certain amount of bounce, which is why all vehicles are fitted with struts &/or shock absorbers, those are what control the bounce. The problem is that many people, when they choose shocks & struts in a cheap lift, choose them based on length and pay no attention to valving - if that's not your buddy's mistake, his shocks & struts were worn - or - he was also using a different spring.
Leans bad in corners - I'm betting your buddy removed the front sway bar - a fairly common modification on Vitaras because it limits flex on the front suspension, and one, by the way, that I do not recommend on daily driven vehicles.
The Tacoma that kept hitting the bump stops - if you lift a vehicle you increase the distance the suspension has to travel before coming into contact with the bump stops - so you really should not have been hitting the bump stops if all that had been done was adding spacers - something else had to have been changed.
I get the point - you don't want a "cobbled" together lift kit - you want something that has been properly designed & engineered - it's your money it's your choice - go with the Calmini if that's what you want.
The spacer kit from Low Range Off Road includes spring spacers, strut spacers (it reuses the OE struts, which are matched to the OE springs), plus all the hardware to refit the suspension brace, and you can buy it with or without longer rear shocks - I have not used it personally, but I can assure you, it has been well thought through - it's not a cobbled together DIY lift.
What I run is the OME - reputedly the world's best - springs, shocks & struts - all engineered to work together - gives me a small lift (approx. 30mm), increased load capacity, and longer travel on all four corners - less than $800 from Low Range Off Road.
Do your research, OME are among a very small number of manufacturers who can supply struts & shocks, tuned to the specific vehicle/spring combination and that actually have longer travel than stock - that travel is what translates into flex.