If you have to Mod an amp then why not buy another amp that sounds like what you want in the first place ?
This a good question and also a commonly asked question. Not o answer a question with a question but allow me to pose this question as food for thought.. What if there is not an amp that sounds like a Modified Rectifier?
I paid too much for my Mesa's to have them altered. These amps are expensive enough.
I completely understand where you are coming and your opinion is certainly more than valid. Many players, myself included, have bought-n-sold a number of different guitars, pickups, cables, amps, cabinets, speakers, effects, etc in search for the tone that we want. Those who have taken the time to make a list of all the gear they own are often times surprised at the total amount of money spent on their quest for the grail-tone. By comparison a Modification may be looked at as a small price to pay for achieving the tones that players have been looking for.
I think often people like a change because it is something different ( like going from el34 to 6l6 etc) but modding a Mesa seems like someone looking for some secret sonic magic that just does not exist.
I will be the first to say that Modifications are not for everyone and it would be misleading if I said they were. I can honestly say that there are a number of well known/pro players to players jammin' in their bedrooms that are enjoying the benefits and advantages that the Modifications have given them. We talk and work closely with players to better understand their individual needs, the kind of tones they are looking for, what their overall rig consists of, etc and this allows us to better serve as well as meet their needs. In short, a Modification will not create a great player, but it can inspire one.
Food for thought
Trace