13,
Why not buy Spaz's maps and compare and contrast between his and a 'custom' map? Which such a modified engine, who knows you may find that some maps are better than (gasp!) one 'tuned' at a dyno shop that shows decent peak horsepower but with not a lot of emphasis in low-mid part throttle response.
If you do get it tuned a dyno shop, make sure you get an Air/Fuel readout, both at peak and, say, 40% throttle. But don't ask for the 40% throttle map (with air/fuel) until after the bike is 'done'.
Just something to consider.