The PROformance Upgrade Kit includes many items to update your Losi Tenacity* to a race level vehicle. This includes an aluminum chassis, which provides more strength, and the items needed to convert to the upgraded chassis. It also includes aluminum front and rear shock towers which stiffen up the suspension for better handling. The aluminum shock bodies and shock caps it includes make for a smoother suspension. Finally, it includes adjustable turnbuckles and sway bars which add to the race-level experience!