I'm going this weekend to get my car custom tuned to 93 and was wondering does the mds function the same with a tune?

 

Why are you taking it somewhere if you're just getting a little bit of tune? You could have easily done that yourself with a handheld tuner. MDS will continue to function as long as you haven't changed any hard parts. Your personal choice whether it shut it off or not if the engine is still stock.

 

I have a 2.5 inch exhaust system instead of the 2 1/4 stock one and a volant cold air intake do you think it would be worth it getting a custom tune?

 

Always worth getting a custom tune, they respond to it pretty well if it's done right. Your stock exhaust is 2.5"........every stock exhaust on a 5.7 vehicle is 2.5". The SRT's/Scats have 2.75". Just keep in mind if you have a shop do it directly, you have no control over things. If you need to take it to a repair shop or the dealer, if thy reflash your PCM you're screwed. If you decide to go on a long trip, with a handheld tuner you could turn MDS on and off as you desire. Longer trips is where MDS really shines. I have an SRT that I can drive two states away and back home again on one tank of gas if I keep my foot out of it.

 

do you think the diablo tunes are safe? I mainly just want to get it tuned to 93 because 93 is 20 cents cheaper than 89 at costco where I mostly get gas and also to firm up the shifts a little

 

Very lol. Otherwise they would've been out of business long ago.