The Rotrex has so many good points. Sure it won't make the mid-range punch of a properly sized turbo, or the off-idle torque of a roots/twin screw, but it has several things going for it. I had one on my MR2 Spyder for a good while, before I went with the 3.5L V6 swap.
1) It's quiet. They use planetry rollers with traction oil, instead of gears. So there is no gear whine like other superchargers. I view this as a plus, I like the sound of the engine not to be drowned out by the SC. It will make the engine quite a bit louder and more "serious", lots more induction sucking sound and louder exhaust. The sound is awesome, and this is a huge plus IMHO.
2) It is reliable. Self contained oiling system with oil cooler, reservoir and filter. Alll of the components are compact, and can be installed easily. Rotrex is also the OEM supercharger for the Koenigsegg ccx (although they use two of them)
3) The boost ramp is much better than typical centrifugal blowers. The planetary rollers, high gear ratio, and well designed compressor housings allow the boost to ramp up quickly.
4) The use of restrictors. You can place a restrictor on the compressor inlet, which allows a maximum air flow, thus limiting the maximum boost. This allows you to use smaller SC pulleys to spin the SC up to higher boost numbers at lower RPM, but not have some stratospheric max boost. For my build, I used forged 9.0:1 pistons, so I did not use a restrictor and boosted up to 17psi. However for a stock bottom end with high compression, the restrictor makes perfect sense. Imagine a pulley capable of delivering 15 psi at redline, but with a restrictor keeping it at 8psi instead. You will probably see that 8 psi pretty early in the mid-RPM range and then it will hold that boost level. HKS has information about restrictors.
5) Packaging and heat. The compact packaging allows for good placement in the engine bay, and makes it easy to install an intercooler. Also, the SC produces MUCH less heat than a turbocharger. This leads to a more reliable setup: Easier to keep temps in check, less "baking" of engine bay components, better intake air temperatures.
I think a 250 rwhp Rotrex kit would be perfect for this car, IMHO... And, if they so chose, power-mongers can change out the restrictor and pulley along with a built bottom end and go for 350+