Objective Engine Discussion

I wish to begin gathering UNEMOTIONAL, tangible pros and cons on
engine choices for my Cozy Mk IV. I won't be ready to begin working on
my firewall for about 12 more months.

As I see it today I have the following engine choices:

Lycoming 360 or XP-360
Mazda 13B or Renesis
Jabiru 5100
Subaru ???

My background:

- I don't know squat about engines - all I know is that they are big,
heavy, expensive, you add gas and oil, and it makes the big fan go

Issues I DO NOT want to discuss at this time:

- Resale value
- Religious discussions of using "standard" aircraft engine vs. auto
conversion.

Here are some questions I have at this time:

1) Fuel - Can the XP-360 use autogas? Can the listed auto engines use
100LL? For those of you using an auto engine - how do you get autogas
to your plane?

2) While I hope to learn a lot more about my engine, whichever I
choose, I don't expect to learn enough to do all work myself when it
comes to maintenance. Obviously, the XP-360 can be repaired at most
airports. For those with auto engines, what options do you have for
repair?

3) Living in Denver, I expect to fly above 10,000' quite a bit. Am I
going to want a turbo auto engine? What is equivilent for the XP-360?

Here is my current list of Pros/Cons for XP-360 vs. auto engine:

XP-360

Pros: Fairly standard, mostly plans install. Improvement over true
Lycoming. Get repairs at most airports. Get 100LL any airport.
Cons: Expensive repairs.

Auto Engine

Pros: Newer technology. Much cheaper repair. Cheaper parts at local
auto parts store.
Cons: Smaller knowledge base. Huge deviation from plans install. Might
need custom cowling. Where to get repairs? Where to get gas?

Comparisons that I see as a wash:

- Initial installation costs will end up being about the same.
- Installed weight/CG will be about the same.
- I know nothing about either so I have the same amount to learn.

I'm sure I'm missing some things here (and that is why I'm asking for
help).

Again, please keep answers and suggestions as objective as possible. I
don't want to start religious battles with this thread.

Thank you all for the help.

__________________
Rick Maddy
Denver, CO
Cozy Mk IV #824 - Chapter 19
http://www.maddyhome.com/cozy