The head gasket isn't an issue at all.

Wrong motor for the car. No 1st gen MX-6's had V6's. So it'd be a helluva lot of customization to make it fit, if it ever would.

You want a F2 or an F2T. Or, if you're lucky and have a few thousand more to spend, get the jspec motor.

AND GO TO MX-6.COM!

And like I said, you can't just drop a turbo motor in your n/a chassis. You need the transmission, and that means different axles, and different hubs. For the turbo, you would need the ECU related stuff as well. It's not as simple as throwing a turbo on a n/a motor, nor dropping a turbo motor in.

The n/a motor and turbo motor are generally regarded as the same motor, apart from compression, and I believe the connecting rods on the turbo are better. Dunno, no big deal if you change the pistons, get the rods too I guess. Sure you could turbo the n/a, but then you can't boost as much.