E36 6"x9" speaker recomendations

[MilesP 13]

Hello all.

First off the following is what I have.

1996 e36 BMW 323i.

Head unit: Panasonic CQ-RX320W

http://www.panasoniccaraudio.co.nz/cq-rx320.html

Speakers: Standard BMW speakers. I have the system with speakers in the foot well and one mid range speaker in the door. My rear speakers are the standard 4" speakers. I have purchased an adapter from here http://www.ebay.com/itm/170872080267?ssPag...984.m1439.l2649 and it will soon be on its way.

I am planning on upgrading to some 6"x9" speakers but I am so unsure where to start. I have read a lot around the internet but I am wanting some solid recommendations from people that have had first hand experience as to their quality and their sound.

My budget is around $80-$140.

My friend has a second hand pair of Vibe SR69 speakers that he is wanting to sell to me for $100. http://www.ebay.com/ctg/Vibe-SR69-3-Way-6-...eaker-/69736629

I have had no experience with this brand so any insight here would be great.

Failing that I would be looking at some thing like this http://www.parallelimported.co.nz/car-audi...9-speakers.html

What I am after is not top of the range performance just good quality reasonable sound. I just want a smooth strong bass note. The front speakers are absolutely fine but the system just lacks bass for deep notes.

I don't listen to drum and base or anything like that. My taste in music consists of Kings of Leon, The Horrors, Led Zeppelin, Cold Play, The Strokes etc.

Keen to see what people think! Thanks in advance