EDIT: didn't buy it for full price, did the grind down to 90% off. If how much I spent is your argument, troll else where.
HT -> MT
Engine: 670 -> 810
hp/t: 16.3 -> 19.8
Speed: 40 -> 60
maybe some slight tweaks to to ground resistance and gun handling as well.
Seriously, without doing some rediculous buffs to what is essentially already just a slow MT to force it into being a HT, it would be easier to give the Kranvagn's hull the Kranvagn's engine (instead of the Emil II's historical engine it's currently got; oh WG, you so silly) and top speed.
TL'DR – Rebrand it as a MT and improve the mobility, that's all it really needs to become more competitive
The only other option I see is that it could literally just drop down to tier 8 without a single stat change and be a competitive tier 8 HT. But that would be a logistical nightmare having to refund everyone that bought it as a tier 9.