Objective, 200hp with 4age.

[Bean]

In my humble opinion stay at 288 especially if you intend to rally but go higher in lift - towards 12mm or more. This will require customs pistons and the head reworked (aside from porting, around the lifter pockets too) to go with it but worth it. If I remember correct my friend who does hill climbs is a little over 200hp (flywheel) and has ~13mm of lift.

PS: now I understand why you were interested in my head
I personally have two places for you that I can recommend, Roth Racing in Switzerland (he speaks french too, but rather on the expensive side) or Loyning (one way shipping to Europe is just ~150 US$)

Addition: now that I know what you are aiming for I'd guess my head would have been a bit shy on your goal as additional work would have been needed. If you are not restricted to 200hp go for a bit more ~230 as this will be at no extra cost. I will ask my friend to see if he can give me a ballpark figure how much money is needed (Roth Racing engine). Also a tear down between seasons I think is necessary even if the engine is not in need of a rebuild, as the last thing you want is entering the next season just to have your engine fail on you after a few races and cause major damage due to a minimal issue that could have been resolved easily in between seasons.

Feel free to contact me via E-Mail as I can certainly point you in the right direction due to my friends racing those engines for many years now. Rallying our cars you will face many other issues so it'll be nice to have one less with a proper 'reliable' (in a race environment) engine.