the 1.9 clutch fork will have to be swapped into the hdi box to operate the clutch, the hdi one is completely wrong...
if you use the rear beam tensioning kit then you lose the passive rear wheel steer...
it's up to you really, I can't comment on it being good or bad as I haven't done it myself
a lot of people tend to sway away from it though on a road car as it makes the rear really stiff, not like stiffing the suspension but the bumps really go through the chassis.... so from what other people have told me, for a daily driver...might not be the best... for a toy car then i's worth while but you can even get solid mounts if your hardcore
so all said and done... it's up to you...my personal feeling on the subject are that it would be the last thing I upgraded and if I wanted stiffer mounts then I'd just go for the solid group a type or stick with standard mounts...