Huh, actually no, I hadnt seen that offering from PMC. This is what Ive been looking at on their site
http://pmcmotorsport.com/nissan-sr-s...rbox-swap.html
The link you posted is only the adapter, no flywheel or clutch. It also has the disclaimer that you need a custom flywheel to use any of those gearboxes.
The kits that have a flywheel and clutch are restricted to those couple gearboxes that I was talking about before. This really doesn't clear anything up, rather makes it more confusing. I wonder if the difference lies in input shaft length or something and thats why the flywheel selection is restrictive? Possibly the input shafts sit in the crank pilot bearing on some trans' where the input shaft on the 420g/diesel boxes sit in the flywheel spigot bearing when used with the sr?
No idea if thats true, just speculating.