If it's a Mexican Std then it will have space for a humbucker beneath the scratchplate. The Mexican Classic series are SSS routed. Whilst a sinner will be able to handle the higher gain, I would image it has the faster, sharper attack that single coils are famed for.
The other option (depending on the guitar) as suggested would be to replace the bridge single coil with a humbucker. There are several pro's and cons to this. You would have to replace the scratchplate with one that is cut for a humbucker (not a major problem), but this would mean that you can fit the humbucker of your choice and if you chose four conducter wiring, add a coil tap and even series/parallel via a three way toggle switch, increasing the range of tones your Strat can give you still further.
As for getting the guitar to sound like Page or Slash is a different matter, as the materials the guitar is made from are different to an LP, as is the neck joint, but a humbucker can help get you into the ballpark.
Speaking from personal experience, I have a VHII in the bridge of my Strat and love it. It's a very mature and musical sound, as the name suggests, imagine the early VH records and thats what it delivers - a Hot PAF tone that will make you want to play louder and louder. However, there are a myriad of options available to you, read through the recommendations made here and speak to Tim and the crew at BKP, they will offer you sound advice (excuse the pun!) and point you in the right direction.
