If you want lowering check out Eibachs, i may have mine for sale shortly but not sure if they fit classics???? Also performance, i would recomend Centre section decat, replacement panel filter K&N, and a new back box. It will give a slight rise in BHP/Torque and better noise. But your never really gonna get bigger figures without remapping especially the torque. This should cost not much more than £300-£400 new
IMHO the best mod to raise torque is an uprated set of headers, approx £500+VAT