How much do you want to spend? Rotella T6 5W-40 is very popular for cycles. I've used it in many cycles for years. Cost is about $22 per gal. It's a Group III (hydracracked - lowest level) synthetic.
Next step up is a cycle-specific synthetic oil like Mobil 1 4T 10W-40 or Castrol RS 4T 10W-40. Those are about $10 per quart. Higher level Group IV PAO synthetic. I believe Redline oil is in this category as well.
Next step is a Euro oil like Motul or Repsol. Their top of the line racing oil (like Motul 300V) is about $15 to $18 (list) per quart. Highest level Group V Ester based synthetic.
I use Rotella T6 a lot, but have Castrol 4T 10W-40 in my SV right now. Motul 300V claims to give you the most power, and I've seen some info that suggests it does.
Can you tell the difference on the street? Probably not.
Jay