first things first I have a pelican sit in kayak, I want to rig it up for fishing now my question is, should i make my mods permanent or removable, would like to buy a nice fishing kayak but won't happen any time soon, so I'm thinking resale value of my current kayak, I've seen removable rod holders ect.

Since your already thinking resale, any mods you make the next buyer may or may not like. I say do what appeals to you.

Make them permanent. I think it'll make the selling value higher one day.

Attaching permanent is better not only for you while you have it but also it does help in resale as the new owner will not have to go out and mod it using more funds.
Also if you learn any plastic welding (it's easy but time consuming) you can always remove any pieces later and use plastic of same color, which you can get from the kayak manufacturer, and weld the holes closed. It is easier with self tapping screws but a little more challenging the bigger the hole you make to put the piece on. So go as small a hole as needed for stress on kayak but for ease of removal later if you need it.

I would do a little research and learn how first. Make sure no holes below water line . Make your mods clean and tidy as if it were professionally done. You certainly can increase value of your kayak at the same time you can damage value. Use bolts, washers and nuts. You have access to the inside of the hull. Screws on anything is an absolute last resort. Just my opinion. Keep any plastic that you remove, drill shavings etc. Put them in a baggy and keep them. Thats color match plastic for filling screw holes or drill errors. Marine goop every hole always unless using wellnuts. Good luck. Check out dfw kayak fishing on facebook also. Mabey between this site and that one you may find a guy who is in your area willing to help.

thank you everyone for your tips, I will go with permanent mods, I just wanted to put some rod holders and an anchor cleat system... at least to start with...