people are always gonna ask. you can model any amp to sound like another in a way. but the main variables (aside from the player and the fingers) are always gonna be amp and pickups/gutiar...
however the recording process is the hardest thing for people to understand how it truly distorts the original signal. unless you record yourself its hard to understand. since i got a studio and got loads of gear in there and am workign on perfecting my engineering skills now i understand. and i also see everything differntly. guitars are always overdubbed and double tracked and there are different mic techniques, some prodcuers eq/compress some dont. room type, etc. etc. etc.
but as complicated as it is sometimes it comes down to basics -< if you wanna sound like slash, start by playing a "deep" guitar like an LP or something of that sort with seymour duncan 59's or alcino ii's through a marshall jcm 800/jcm 900. if you wanna get the jimmy page sound get a marshall 100w master volume head and an LP, if you wanna sound like john petrucci get a mesa boogie rectifier or triaxis or mark iic+ and play through a basswood guitar (ibanez or ebmm) and dimarzio steve special pickups ifyou wanna sound like nuno bettencourt play a bill lawrence equipped gutiar through ada mp1 pre amps and like a mesa 50/50 power amp or something.... etc. etc. you get the point.
people will always ask and you can always point them. can i use a triaxis and an esp with emgs to sound like slash, sure if i spend time eqing everything. it sont be authentic but you get the point.