Adding speaker wire

I am redoing the stereo in my 2013 Tige. It came with a basic 4 speaker stereo with no amp. Clarion deck and 4 WS XS-650 in boats. I am adding an WS Ht-6 for the inboats and to drive a WS sub. The existing speaker wires are connected to the deck and won't be long enough to get to the amp wall which will be directly below the current deck. So I need to add wire to get to the amp. Probably 2 feet at the most. Can I use a high quality(Uline/3m) shrinkwrap butt connector to add wire? I know soldering is probably best but the wires are wrapped in a loom under the glove box inside the observer seat compartment so its really not practical. I can barely crawl in there and the thought of trying to solder in there isn't pleasant. I know the butt connector will work but will it effect the sound quality. It would be just for the XS-650's which will be getting roughly 110 watts each.