Putting two speakers in the dash, when it was only built for one

unless your using a high powered,big dollar system,,,if you have a loud engine or exhaust,the kick panel area seems worth less with a regular or cheaper system,,altho i love music,,played in bands for years,music is not my biggest concern when tooling around to cruise nites and such in my barracuda. so needless to say i have a average indash radio,with an add on 100 watt EQ/AMP,,i have 6x9 speakers in a box directly in front of the wheel tubs on the flor pointing up,and a pair of smaler speakers mounted in the stock dash location, mounting them in the dash location made a huge difference in my car with my small average system over haveing speakers mounted in the kick panel area,and they arent visable,,totallly happy with 2 speakers mounted in the factory dash location as front speakers in a loud car