I was cautioned by Jeff K not to run over about 4lbs of boost unless I installed the forged pistons. Jeff has done probably more blower installs than anyone I know of and I trusted his opinion. JE pistons ran me about $700 for the set then you also have to do the gaskets etc where ya have to split the engine, take off the heads, ... Oh, im running 8 lbs now. The bike has performed flawlessly since the install. Its a bit cold natured though and is a bit tempermental to start in cold weather. I would also suggest changing from the stock exhaust to something like the exhaust offered by Carolina Bike & Trike. They purchased the tooling etc from Thunder Mfg for their pipes. http://www.carolinabikeandtrike.com/Exhaust1.htm
Also, I changed the fuel pump from what came with the kit as did many other blower folks I have talked to. Now, if you got the new kit it may have the carb behind the blower. If thats the case you wont have a pump at all as I understand it. However, if you got the kit with the Keihin CV carb and the J tube it will have a pump in the kit with it. They arent known for being all that reliable. So, after hearing about several folks getting stuck on the side of the road by that fuel pump, I just went ahead and installed a better pump.
If you stay with the stock pistons, the blower install is an afternoon project for the most part. If you go the whole distance, then its gonna take a while.
I also installed a pressure switch and a Dyna 3000. I set the pressure switch to ground when the boost rose to 4psi or above. This let the Dyna 3000 retard the timing.
Here is a list of the changes I made to mine.
JE forged pistons
Viking valve springs
NOS pressure switch (for use with the Dyna 3000)
Jiffy Tite quick disconnects for the fuel lines. (makes tuning much easier when you have to pull the tank over and over)
Pingle Petcock (the stock one starved mine at wide open throttle)
Inline Fuel Filter (since the pingle didnt have as fine a strainer as the stock petcock)
Water Wetter coolant additive.
Dipstick Oil Temp Thermometer
I also double sprung the diaphragm spring on the clutch.
NOS fuel pump
I also installed an O2 sensor in one exhaust bank so that I could hook up a K&N Fuel/Air ratio gauge from time to time while tuning.
Ive done a number of other things to the bike too, but those are the main changes to the powerplant and drive line that I can think of.
Once you install the kit, you may find that it is hard to adjust it to idle properly. Many of the bikes will "search" for an idle. They will oscillate from about 600rpm to say 1500 rpm and back. I ended up drilling a really really small hole in the center of my butterfly (Keihin CV Carb) to give it just a taste of more air. This took some experimentation but after a couple trys I got the oscillation stopped and it allowed me to tune the idle. If you have a similar problem just email me and I will go and see if I can find out what size I drilled it out to. Its been a few years so forgive me forgetting but I would be happy to go play around find out what I did. It was smaller than 1/16th. Perhaps a #54 bit or so. Thats in the neighborhood.
Another thing. The kit will come with a desmog kit. Mic your smog ports on your heads and the plugs before you try to drive those plugs into the ports. The plugs that came with mine were a few thousandths oversize for mine. As a result I cracked a port because I trusted them. Evidently there was a small change at some point in valk production and a size change in that port size. 7 thousandths or so rings a bell. At any rate, I had to get me a piece of aluminum and I borrowed a friends turning lathe and I turned my own plugs and polished them and welded up the crack ... it all worked out in the end, but I got a bit hot under the collar when I cracked that port. So... MEASURE FIRST!
Oh, and as I recall the instructions that came with the kit were pretty vague at times. I figured it out so Im sure you can too. Its not like im some kind of rocket scientist or anything. If ya have a question just drop me a line or call Bill or Lamont.
I hope some of this helps. Have fun. Once ya make the change... you wont regret it