Hiya Jan,
I've fitted a couple of these kits and the downpipe needs adapting to match the rear section correctly. Waste gate is cheap without any pre load adjustment so if you do go for this kit you'll need a better quality WG.
Turbos are journal not roller bearing but they do a good job for the money as have one fitted on one of my Coupés.
If you're looking for bigger power personally I'd look at sticking with the standard exhaust manifold and spend your budget on a genuine GTX series turbo with FMIC, injectors and live remap. You'll save all the hassle with the fitting etc and it'll probably return better BHP/FTLbs numbers once finished.