haha! I'm no professional... I've just done it a few times and learnt the hard way! I'm always a little bit warey of Halfords and the prices they charge. For example, you look on Halfords for an Alpine CDE 103BT head unit - £199.99 (prob even more in shop). www.celstores.co.uk is selling it at £179.99. Its only an example, but I'm sure you'll find the same across many items they sell. Its not to say don't buy from there, just be aware that you can be more value concious, and spend the same amount of money on better items. In fact, I've just done a search on those Edge Speakers: £40 from Halfords, top hit on Google - £35 from caraudiodirect. The speakers look ok. I've never come across the make before, but the magnet on the woofers seems to be a reasonable size, and they have a power handling capacity greater than you'll ever need. They do look a bit 'bling' to me, which probably needlessly adds to the cost. When you consider you'll never actually see them, bling isn't so important. I assume the yaris has a component speaker set up from stock (ie a woofer and a seperate tweeter in each side at the front). If you've only got 1 speaker each side, the easier way to go is get a composite speaker, with the woofer and tweeter(s) is a single unit. Consider replacing the rear speakers as well as the front ones. Some people like the "sound stage" idea, where you can shut your eyes, and think you are at a gig, with all the sound coming from in front of you - this would be a decent set of front speakers only, and fading all the sound to the front of the car via the stereo head. Some people prefer a very full sound and have the cabin full of noise (my preference), so in this case, you'd want to replace all stock speakers in the car. If you do replace them all - go for the same brand and same series of speakers - don't mix and match brands without good reason, otherwise it could end up sounding wierd. The Sub also looks ok. The "speaker and box in one" packages will work well together - the company that makes them will have invested time and effort to make the items work well together - better than you buying a sub speaker and a box for it to go in if you are a newbie to this (yes, the box you put a speaker in makes an unbelievable amount of difference to the sound the speaker gives! Get the box wrong, and it'll sound rubbish!). Vibe tend to have a good rep, and its a reasonable price point (although its £87.99 on caraudiodirect!). Bare in mind you will need an Amp to drive it, and a stereo that allows an amp to connect to it (usually a stock stereo doesn't have that fuctionality). If you don't have a stereo with a additional unamplified output to plug in to an amp, you can buy amps that will take a feed from your existing rear speakers (as well as be able to connect direct to stereos), but I wouldn't recommend it. You can also buy packages that are amp/sub/box all in one. They'll follow similar lines to the sub/box combo's where everything has been designed to work together, so would take another difficult decision of 'what to get for an amp' away from you. And finally, I've noticed Vibe also do a package of Sub/box, with seperate amp, and a wiring kit (http://www.caraudiodirect.co.uk/vibe-slick...m-pack-0-1.html) for £160... There will be other examples of this kind of set up as well, so don't assume its the only one - i just haven't looked for any more. So, I guess all I've done is open your options up a bit rather than give you any definate yes's. What I'd do now is get yourself out and about a bit. Go to local meets, and have a listen to what other people have and find out how they have done it and how much it was - it may give you a shopping list of exactly what you want, and you'll know what to expect cos you heard it. Your local cruise scene is probably the easiest way to get that done. And go find some shops that sell this stuff. If they think there's a sale on, they'll happily demo stuff for you as much as they can and give you some sound recommendations for your car and budget, but bare in mind that accoustics in a shop are quite a bit different to accoustics in a car, so you will only get a rough idea on sound from shop demos. And last but not least - if you do decide to go for this big time, especially with replacing the stock speakers, invest in some dynomat to deaden the unwanted sound resonation in the doors and car panels and air gaps. Worth every penny. Good luck with the research!