It is a pretty spendy venture to put a diesel in a zuk. gathering parts from this rig and that rig, plus having to buy or make everything to make it work in there is spendy!
Glenn at Rocky Road bought out the people that used to make that kit, so that means he has cut every single corner possible and jacked the price up on the kit. He is the only suzuki guy I will not buy any parts from or have any dealings with. Customer service is poor at best too. You can search pirate for "RRO" or "Rocky Road" and see what i mean...
I understand you have the motor, but other options are way cheaper and easier to do and you can get the same power or more from.
I dont think its that much, considering that the rabbit was only $25 and the zuk was $200. I think just the gas mileage would be enticing enough to go through it. I had a friend that did it and he loved it. Until he fell into some financial difuculty and had to sell it.