opinions on my proposed sustem noob

Hello - I would really appreciate any help you guys could give me. My car is a 1995 BMW 325 convertible. Being a 'vert there is limited space (especially for rear speakers!) A smaller amp would also be ideal, as I have limited trunk space as well. My proposed system: Head Unit: I have a high end (for Kenwood) Kenwood head unit with plenty of outputs etc. I'm thinking for my fronts, either Focal or Diamond Audio component speakers. I'm going to go with 5.25's, stock size. For the rears, same brand as front but I was thinking some conventional (non component) 5.25". Question: Are rears really worth it with good quality fronts/amp/sub? Sub: One sub either in a custom enclosure in the ski pass through (common mod on these cars) or (more likely) in a box in the trunk. Undecided at this point. Not sure what brand sub yet. I have a box made for a single Kicker square sub so, I may go that route. Amp: No idea yet (maybe Alpine?) but I would like to avoid two amps so, I could get a four channel and run the two front components off two channels of the amp, then bridge the remaining two channels and run a sub. If I have rear speakers, I would run them off the head unit. Does anyone see any issues with the above mentioned setup? Advice would be GREATLY appreciated!!! Thanks! Brian

I've been researching and I think I may go with the CDT Audio CL-E51NEO 5.25" speakers for the front. Opinions on there vs. Diamond Audio component speakers? Thanks again, Brian

I dont know,im kind of biased towards the diamond audio components because thats what im running now (hex S600s series) and i can tell you they sound awesome with a little bit of power behind them. however ive never heard the CDT components so i really couldn't tell which is better. the only thing you can do is try to listen to both of them and see which one you like best. other than that you have a good setup idea with running the components and the sub off of just one 4 channel amp. ive seen plenty of people do this with good results.