Another option to do in-place downgrade without any new instances  is to use registry keys 
http://sqlserverstore.blogspot.com/2013/12/how-to-downgrade-sql-server-2008-r2.html

We used this approach 4 years ago to downgrade about 20 servers...

thanks for idea, Andy!

I have the almost same task to set Transactional replication non continuous.

It turned out that logread.exe doesn't require Ctrl+C command at least in SQL2008R2.

So, I've just removed...

Rudy, hi!

Regarding this portion of script :

-------------------------------------

--> SQL Server Settings <--

EXEC sp_configure 'show advanced options', 1;

GO

RECONFIGURE;

GO

SELECT

[name]

,[description]

,[value]...

8039 😉

http://www.sqlservercentral.com/articles/Miscellaneous/pagesize/497/

why not

((totalextents-usedextents)*64)/1024)

instead of

((totalextents*64)/1024)-((usedextents*64)/1024)

?

SQL Server Survival Guide : http://www.akadia.com/services/sqlsrv_programming.html

You should use stored procedure xp_cmdshell

books online : infocenter.sybase.com