Finally was able to figure out my thread size through searching countless threads and ordered this beauty. Only gripe is the plastic piece that is there to hold up the stock shiftknob but I can live with it. Looks great in the center console and feels great too.If anyone is wondering, the thread size for the 3IS is 8mm x 1.25mm Here is a pic:

 

Thats pretty dope, link to the website you got this from?

 

I actually got this off Ebay. They have 1-7 star dragon ball shiftknobs in the 3IS thread size. Came with a Jam nut too. Here is the link:

http://www.ebay.com/itm/Dragon-ball-Z-rare-custom-52mm-shift-****-7-star-M8x1-25-automatic-transmission-/221662884240?hash=item339c233190&vxp=mtr

 

looks like there is a bottle cap inside it... Is it plastic?

 

The threaded insert is metal. You're right though it kinda does like a bottle cap, or an updside done reeses peanut butter cup.