I have a pair of Harimau made on order by Freewave.
The build is excellent with a very stiff shell.
Freewave makes only custom or semi-custom boots so they can be adapted to your feet. You can have a very snug fit.
I use these skates together with Seba KSJ WCE.
The ankle/cuff part of the Harimau is stiffer than the one of the KSJ with less rear/front flex. The upper part can be compared to the upper part of the original Twister, i.e. no cuff and relatively high shell inside but without removable inner boot..
As you can see on the pictures, the inner side is shaped to fit the foot shape with cups around the malleolus and made with a very stiff foam. The tongue foam is softer.
The red material on the tongue is a kind of rubber scratch that prevents that the tongue slips.
The boots are slightly lower than the KSJ so, with the same frame, your foot is slightly closer to the ground than with the KSJ.
Harimau boots are the lightest on the market, they weight less than the KSJ boot (728g vs. 840g for KSJ size 43, Harimau are custom so no size but equivalent to 43).
The Ikran frame is rockered and weight less than the KSJ frame (205g for the 242mm 4x80 vs. 248g for the Seba Deluxe/KSJ 976 frame) but the Seba frame is stiffer. Note that a part of the additional weight of the Seba frame is due to the steel axle vs. aluminum axle for the Ikran. Honestly, I never understood why Seba uses steel axles because aluminum axle are strong enough especially for slalom, all other manufacturers use aluminum axles.
Some more details below: