The speed brakes are just that. Without them, the plane is noticeably faster & has a longer & flatter glide -- it floats more. With the brakes on, the descent is steep & slow -- great for spot landings, but really bad if you dead-stick any distance from the runway.

The wing cuffs also cut top speed, & not surprisingly, reduce landing speed -- it's quite a bit faster at full throttle & noticeably faster landing without them -- again a longer & flatter glide (still more float).

Both brakes & cuffs affect agility and seriously degrade inverted flight capability, although at that stage, students won't be doing anything needing serious agility & won't be flying inverted. With the brakes off, & the cuffs on, the Nexstar has reasonable inverted capability & is agile enough for simple aerobatics. With everything removed, the Nexstar is pretty fast for a trainer -- just about 70 MPH, and once the throws are cranked up it can do quite respectable aerobatics, including hovering, a wobbly knife-edge & outside loops.

The plane needs re-trimming when the bits are removed, but this is to be expected.