My '07 S40 seems to chirp the same way, that is, with power on. It almost seems to chirp at the same rate the engine fires, for what that might be worth. I attempted the method of adjusting the rear wheel alignment to center the belt, but ended up with odd handling. Centering the rear wheel to run in line with the front cured that. Now the belt runs on the left side of the pulleys. Belt tension doesn't seem to matter much - I have tried it with the Suzuki-supplied gauge, and with the 90-degree-twist method and now have it between the two. Note that there is only about one turn of the adjusting bolts difference. Careful listening locates the squeak as coming from the left edge of the front pulley. I tried Dupont's Teflon Multi-use dry wax lubricant, and it seems to work well enough. It is sold as a lubricant for O-ring chains, for which it works also. My long-term solution may well be to lubricate the belt to make it quiet, then sell the bike and call my 250 Ninja prime mover.