I have the Al and STiR+ systems working together..and also find myself in the same situation as yourself with my second AL install (currently running V1)..to get another STiR+ integrated or stand alone...
I have been messing with V1 LE and Sealth and find myself ultimately trying to emulate the GPS function of the BEL...and of course I can't do it...or can't do it well or easily...but that is for another discussion..
I guess one aspect is the type of driving you do or rather area of falses...if predominantly highway then the integrated would suffice and work well but for me at least the ability to lock out is the breaking point..as I spend alot of time on the phone in the vehicle I just hate falses when trying to concentrate on a discussion..and...to add the breakout box for the AL later is not that big a $ hit...
Then there is the aspect of GPS on the AL you didn't mention for speed threshold radar setting...and red light / speed trap setting on the STiR+...too many options