Newbie Question - Gen III/IV Viper Aftermarket Support

Hello, brand new member here. First post. Looking for some help but more so looking for some peace of mind on the subject. I have always been in love with the Gen III and Gen IV Vipers. I've wanted one for the longest time and I with just 1 year left before I can retire from military service, I am ready to pull the trigger on one.

My question is, how is aftermarket support for these cars? I am pretty sure I already know the answer but wanted to come here to ask actual owners with experience. My concern is, since Vipers are no longer being produced, will that make long term ownership of these cars more complicated with respect to finding aftermarket repair parts? I typically keep my cars a VERY long time and just do not want to have headaches when repairs are needed. I assume aftermarket parts (mechanical and cosmetic) are abundant and readily available?

Also, I am shopping gen III and IV Vipers and keep reading about how many mechanical improvements were made to the gen IV cars. I also notice they come at a pretty significant premium over the gen III cars. Any reason to avoid a gen III car if I find a great deal on one or should I absolutely focus on finding a gen IV.

Thank you all so much for your time, would love to hear your thoughts/suggestions, etc.