The SR has been out of production for awhile now.

As has been stated previously, most choose the CA for registration purposes. Other reasons are that they are significantly cheaper than an SR to purchase and fitting kits and knowledge are quite easy to come by because so many people have done the conversion.

You are correct that it is easier to get parts like Power FC's, winged sumps etc for an SR. I'm sure this situation will only be tipped more in the SR's favour as the years go on too. That doesn't mean the same parts are not available for the CA, it just means you need to look a bit harder.

It's a tough decision so, if you can, get a few rides in different converted cars to see what you prefer.

Good luck with your decision mate.
Regards Matty