Which one is better for conversion?

I have 3 Ryobis and 1 McCulloch. I plan to use an electronic ignition from CH on either one I choose. I've been told that the Ryobi will not develope the same HP as the McCulloch, but the Ryobi is lighter.

I can get a muffler and ignition for each of these from CH. I've read some of the things that you can do to the Ryobi to Hop it up. I haven't read anything about doing hop ups on the McCulloch.

I'm really wanting to do a conversion on the easiest one. I might be all wet here, but the Mc looks like it would be harder to convert.

What do you guys think?