Suspension systems and parts specially adapted for suspension systems for land vehicles, namely, base strut coil spring boosters, heavy duty coil spring boosters, coil spring expanders and tensioners, front rubber coil spring boosters, rear and front twist-in coil spring boosters, leaf spring clamps, leaf helper springs, over leaf spring assists; parts specially adapted for suspension systems for land vehicles, namely, square u-bolt kits comprised of square u-bolts specially adapted for suspension sysems for land vehicles, and also including metal nuts and metal washers; parts specially adapted for suspension systems for land vehicles, namely round u-bolt kits comprised of round-u-bolts specially adapted for suspension systems for land vehicles, and also including metal nuts and metal washers; parts specially adapted for suspension systems for land vehicles, namely, lift and lower block kits comprised of lifting blocks, lowering blocks and round u-bolts, each specially adapted for suspension systems for land vehicles, and also including metal nuts and metal washers; parts specially adapted for suspension systems for land vehicles, namely shackle kits comprised of leaf spring shackles, and also including metal bolts, metal nuts and rubber bushings; parts specially adapted for suspension systems for land vehicles, namely, universal leaf spring lift kits comprised of leaf springs, and also including metal bolts, metal nuts and rubber bushings