Going in on eBay electric ignition for 650SR. Suggestions?

1978 KZ650SR.

These bikes have basically little to no resale value so sticking a big $$$$ electronic ignition on it makes little sense.

There are ebay kits to convert the points ignition to electronic for $60 or so. Has anyone where had good luck with an ebay seller or should I just do the usual ebay due dillagence?

I have a parts bike 1979 KZ650SR but never looked to see if that is points or electronic ignition.

Suggestions welcome.

Is this the "Copy" Dyna "S" ? - if so there are a few posts regarding these, generally people seem to have done OK with them

I've fitted several of the Chinesium Dyna systems to bikes for people. Never had one fail electronically only had one cause an issue where the trigger magnet fell out. Glued it back in and been good ever since. 

Well, there's a lot of different prices. The 4into1 kit is $300. A basic china kit is $54. Any suggestions?

The 4-1 kit is a real Dyna Ignition but with chinese copy coils and leads.
Most of the cost there is due to the genuine Dyna ignition.

Your original kawasaki coils will work fine with the copy ignition plate. 
There's plenty of resellers of the Chinese ignition plate which all come from the same Chinese sweatshop. 
Take your pick from whichever has best price/delivery time. 
Just make sure you buy the correct one for your 650 as the one for 900's  is a different diameter backing plate. 

The $50 one comes with zero instruction and 4into1 doesn't do any customer support after the sale. I learned this the hard way.

What would a guy do if he opted for $50? What comes off, what goes where?

As it's a copy of a Dyna the fitting should be similar - There are several videos of "how to" on YouTube and also I have included a Dyna wiring diagram





 

You can download and print the fitting instructions off the Dyna website. 
Fitting the Chinesium one is exactly the same. 
 

It would be a good time to add a relay and fuse to the coil power supply wiring while you're installing your ignition.  Plenty of posts here covering the addition.
BTW I installed one of the 45 dollar no-name Dyna copies and so far so good.