I am no expert by any mean, but AFAIK the transmissions are the same, you can just drop the V6 in there and mate it to the existing tranny.

 

It will be cheaper to jus get a v6 beater tib. There is quite a bit to swap out, and honestly the beta motor is a fantastic motor. If you take care of it, and research proper upgrades, you'll have one great tib. But swapping to a v6 is not cost effective. But if you want to tool around and do it in your driveway, more power to you, go for it. But if you're looking to not spend money on parts you already have, build the i-4

 

the v6 is a 60 degree aluminum block with thin cylinder walls. probably not going to hold a lot of boost but you will get plenty of torque at modest hp levels.
the cost of swapping is quite high however, so i'd recommend not doing that.
the i4 is an iron block closed deck design and doesn't need sleeving to be run with higher boost pressures. if you want to put a turbo on the motor, this is the one you wanna pump with the turbo.

If you still want the v6, it's about the same price to swap a v6 into a 4 cyl car as it is to just buy a v6 tiburon these days since you have to get the ecu and additional electricals (ECU, wire harness, distributor, etc.) to operate the v6 as it's supposed to.

for the time and effort, not to mention the price, it's less pricey, even including insurance, to find a second tib as a v6

 

The cylinder walls aren't really that thin but for him he should probably just get a v6 tiburon if he wants it rather than swap

 

the walls are comparatively thin. probably won't actually experience cylinder wall issues at something like 18 psi, but it's something.

 

I'm mean comparing it to other engines not really, the sleeves actually have a little bit more thickness then people think, compared to some engines like some Honda engines and others just have an aluminum cylinder liner with a coating added to it and it holds , the 2.7l at least had a actual iron liner inside of the aluminum block not just aluminum like some and compared to others that have iron liners its actually average thickness