I have a Miroku model 1863, but I bought it completed, not as a kit. These are very well made guns, far better and more authentic than anything coming out of Italy. The italian guns are all overweight by virtue of denser, heavier wood and thicker barrels. The Mirokus are made to original dimensions and are almost identical in weight to originals. I also have a Miroku Model 1861. I can hold either Miroku in one hand and my Euroarms M1861 in the other and immediately tell a notable weight difference. The Euroarms feels like a boat anchor.
Downside to a Miroku M1863? - the stocks are two piece, joined under the lower band. I permenently joined the two parts with steel pins and epoxy. Spare parts are hard to find, but are rarely needed. Some lock parts are very similar, but slightly different from originals. They are forged too, not cast like the Italians. The Miroku is a M1863 type II. But it has a split lower band, but it should be a solid band. Not sure why they did that. But an original solid band is not hard to find.
If you are not interested in reenacting, it doesn't really matter. But for reenactors, these are not real popular because they can only be used in later war events which limits their utility. I picked mine up used because it was a good price. I use it for late war events occasionally, but also lay it out for living history displays.
Overall, they are a very well made musket. Miroku doesn't make them anymore. Dixie must be selling the last of their stock.
Good luck!