A couple of other thngs to be aware of if you decide to go inverted:

1) You may want to install the fuel tank lower in the fuselage. The carb on the inverted engine will be below the centerline of the tank, which could lead to fuel siphoning down through the carb. This could cause flooding/hydrolock when starting and/or running rich at idle. Since you're building a kit, changing the tank location is easier than if it was an ARF.

2) Starting an inverted engine is more of a pain than an upright/side mounted engine. You can't easily see the glow plug when the plane is resting on its landing gear, so connecting the glow starter can be harder, and getting it off means you're reaching under the plane with restricted clearance, etc, while the prop is turning. You might consider the use of a remote glow connector, or putting a glow driver on the engine. The glow driver might also help with low speed operation if the fuel siphoning problem mentioned above rears its head. But there goes the $50 you saved with a TT or Magnum.

3) But the good news... sideways or inverted, you can build a cowl for the Tiger and it'll look really good!