My only worry is that it will look tacky or gimicy.

We’ve got a black Mitsu L200 at work and it’s a perfectly decent black—doesn’t look much different to my 944 when they’re parked together

I would ordinarily say stick with the original paint colours that Porsche used in other words if you're gonna go black use their shade of black but having owned an alpine white 944S (now gone to the classic car graveyard in the sky) I would agree that other shades are sometimes better. I would park mine up at work and one of the other lads on the watch had a white Audi a3 and if he parked it next to me it made mine look like it had lived it's life in a pub vault smoking serious amounts of woodbines, yet on it's own it looked like new (copious amounts of 3 stage meguiars). I think at the end of the day it's all about personal choice, like the others said get a sample off them, your spending enough money.

My 944 is Alpine & it is a dirty white, hence the respray is in RAL 9010 which is a more brilliant white. Paint now bought & sitting in garage so no going back now.

You're offering good advice, but are your L200 and 944 pearlescent? Going 'normal' black is fine, but the bit he's worried about is the pearlescent effect.