Yes it would in most cases void or cause problems with engine warranty. But these are "piggyback units" they plug in in between the ECU and injectors and fool the ECU so there are no changes to the ECU, if it is removed before going into the dealer it is undetectable. It is usually a 10-15 minute job to unplug these type tuners.
This type of tuner has been used for years in the MC world , especially in the later 2000 model and newer Harleys and if removed there is no way for the mechanic to know it was on the bike. But this type of tuner is also very limited in what parameters it changes , the actual remaping of a ECU or a replacement ECU will make more performance and will alter more parameters.
Lap 3 just release the ECU tune for the LF models and there are big increases, HP +40 and Tq +70 if i remember the post, it also changes the boost limiter in 1 and 2 gear and shift points. But this is very detectable by any scan by the dealer or mechanic and to change it means swapping out the ECU. So to buy an extra ECU and the tune it will be over $ 1000