Installing a U-joint correctly more often than not requires special tools these days, and potentially a rebalance. Also, replacing U-joints without distorting the driveshaft yokes and the aluminum tubes requires more care to prevent damage.
It is better to take your time and use finesse rather than brute force. Otherwise, you may see it again when the customer complains of a vibration.
Check out these tips and techniques for replacing u-joints from our sister publication, ImportCar.