I can vouch for the Pioneer TSC160R (kevlar splits) - they'll drop in apart from the back trimming that I referred to before, and they sound great. There are also some gorgeous Rockford units (the model number I can't remember), but they are 6.5" and will require a trim around the speaker hole as well. Either of these though (around the same price range) work really nicely. I've not done any work with Alpine, but they have a damn good reputation - they are spendy though, I think a bit of what you pay is for the badge.
For something a little more "wallet friendly"
, I can also attest to the Jaycar (Response) 6" or 6.5" kevlar splits - again,. the 6" will require just the back of the pod trimmed to clear the magnet structure, the 6.5" will need about 5mm trimmed all the way around the mounting flange. In my own opinion, the Response brand well out-perform the Pioneer units of the same price range. (the TSC160R I referred to above are about double the price of the Response... they are appreciably better though)
Best of luck! Cheerz.