and where does one find these bars?
do you find the straight line ride suffers or becomes harsh?
As already stated, this, or any sway bar regardless of stiffness, will have absolutely no effect on your straight line riding, suspension or otherwise. It is nothing like a stiffer shock spring (which will greatly affect your straight line ride).
An anti-sway bar is completly neutral until you enter a turn. Then it goes to work countering lean and wheel lift. The effect is progressive and with this custom sway bar, quite impressive.
Slow, mild turns will receive a small effect from the anti-sway bar. Aggressive, high speed manuvers will get a greater amount of reaction. It is a seamless process. You feel the results as a flatter, more controlled turn.
The effect is increased or reduced based on how much the Spyder tries to lean. The harder the turn, the more your Spyder wants to lean away from the turn and lift up the inside wheel. The Anti-Sway Bar effectively transfers 'Weight' from the outside wheel to the inside wheel (and to a lesser degree, the rear wheel). This gives you a flatter, more controlled and effecient turn.
The difference is amazing. The harder you turn, the better this custom anti-sway bar gets. Instead of the front, outside tire getting all of the traction duties in a hard turn, the inside front tire stays put with authority giving you more traction and steering tire contact with the pavement.
Because lean angle is greatly reduced, your Nanny will bother you less as well. She is still there to slap you down, as always, she just lets you have a little more fun before she gets upset.