Towing under 2500lbs - Perf or tow tune?

[goracer]

I forget where I read this but I thought I rememberd reading the preformance tune can tow up to a max of 2500lbs, is that correct?

I am trying to decide which tune or if multiple tunes are needed, then which of those.

So far my best milage has been:
18.1mpg on 87 with canned Evo level 2 tune and a max of 60mph fwy 20 min.
19.1mpg on 87 with canned Evo level 3 but retarded -2 @<60mph fwy 20 min.
??.? mpg on 91 with canned Evo level 3 tune and a max of 60mph fwy 20 min.
...will test 91oct mpg tonight.

Towing:
Current - Only a 400lb motorycle (lifted bed too high) plus the trailer.
Future - If money holds out is a 2800lb car plus the trailer (4,000lbs?)

Wants:
Towing is confusing as you loose alot of MPG towing but sacrificing power is probaly worse then milage.
Daily driving would most likely go with lowest cost per mile but how much of a sacrafice on power is that?

Questions:
Can I tow my motorcycle (500lbs) on a performance tune?
Can I tow > 2500lbs but < 5,000lbs on a performance tune?
Should a tow tune be mpg or power?
Which yeilds the lowest cost per mile 87 or 91? ...prolly find out tonight.
How much of a sacrifice is mpg in towing vs power in performance?