Which strut brace ?
The top front, lower front, or rear ?
The benefit of a strut brace is that stifens the chassis when its in motion (ie. corning) so it improves handing on corners. If you like driving fast, it is the cheapest and simplest performance improvement you can get.
It is said the biggest improvement is from the lower brace, and the least from the rear. I think both the front ones are important, but the rear is is a bit of a placebo in normal driving
Apart from the rear (which involves drilling) they are very easy to fit, undo bolts, attach brace re-do bolts again.
Strutbracer on this forum sells some OMP braces, so you can ask him about them.
2003 156 GTA Selespeed - Alfa Rosso + black multispokes, Eibach anti rollbars, Quaife ATB diff, 330mm brakes, Bilstein B12, De-cat wrapped manifolds + EQ downpipes + Ragazzon silencer, CDA intake, (carefully) removed interior & Sparco bucket seats + 6 point harness
2002/6 156 JTS Selespeed - Full Ti interior, late model camshafts, Supersprint manifolds, Ragazzon silencer