2000 gse speaker removal help

I have a 2000 gse regal. i need to replace the rear speakers I bought some pioneer ts-a6962r speakers because they are 2ohm and 40w nominal. when trying to get to the old speakers the only problem i occured was removing the plastic tack or screws or retainers. whatever they are called. i spent about and hour and badly hurt finger trying to get just one off. a screwdriver helped but there has to be an easy way to do this. i looked over other forums and it seems that i am not the only person who experienced this. also the speakers i chose seem like the best replacement to me for those of you wanting to know what kind of speakers to buy. my question is how to get off the plastic tacks? my other question is can i hook up two of the wires to the new pioneers and the other two to the 4" monsoon speakers in the back?

Welcome to AF!!

I don't know about hooking the wires up the way you indicated but the best way to remove the speakers it to remove the back seat and pull the rear deck cover out that way. This will allow access to the speakers without damaging the grills. Otherwise you may not be able to get the originals back on correctly.