switching to slalom, sail/board choice

I am finding my most versatile board is my *brd Isonic 90 wood.
I use it with a 6.3 and a 7.8 Loft Blade set on skinny masts and a 32 cm Tectonics Goldwing and 34cm Vector Canefire.

This set up suits my weight 75kg and 176cm for 15 - 25 ( a bit more on flat water)

That said I am GPSTC sailing (speed focused)

If you want to slalom race then a bigger board (perhaps 110-115 +40 ish fin) would be vital.

For 25-40 knots of wind you will definitely need smaller kit (5.6 or even 5 and as small a slalom board as you can get or a speed board)

I recently bought some Slalom gear and i am 184cm and 68kg. I got a 96 litre JP Slalom VIII and a 7.0 Severne Reflex 3 and i use a 36cm Maui Ultra Fin slalom fin. I can use that set up from about 12 knots if it's constant, ie 12 minimum up to around 22-24. It's a really good set up and is very quick and planes very early. The Reflex 3 rocks it blows me away how stable it is and almost makes you feel like your cheating. In saying that i don't have much basis for comparison because it's my first Slalom rig but it's very good and the Slalom VIII is quite narrow in Slalom board terms so handles fairly rough water surprisingly well. I was going to buy an i-sonic 107 but liked the idea of the narrower board so the JP got the nod.
If you want to go up to 40 knots you are going to have to buy a fair bit of gear. The Slalom sails are VERY stable and will hold quite a bit of power right up until that last couple of knots extra which is around the 25 knot range for me on that gear then i start to get overpowered. Once the wind gets there i'm back on the wave gear and loving it. I recommend if you can afford to to keep some smaller wave gear because while the Slalom gear is unreal in the right conditions it's amazing how much you will appreciate the lightness and maneuverability of the small gear when the wind gets up or the water is too rough for the relatively flat rockered Slalom boards. That's not to say you can't sail Slalom gear in fairly rough water but there comes a point where it's just not comfortable and the wave gear comes into it's own.
I love sailing my Slalom gear but no way would i have it instead of the wave gear. Having a bit of both is the go if you can.

Thanks a lot guys.. I think am gonna start with a 100l board and a 7/7.5 sail and i will keep my wave gear (i have 4.2 simmer halo, 4.7 simmer blacktip and a 5.3 simmer icon) to see how it goes. Then i will go from there to see the kind of gear i will need for stronger wind and heavier water condition.

Thanks for the reply and info. I wanted that board so much but was sold. Nice purchase.
Cheers
Marty