Codes P1123 and P1125 on my 99 Boxster
 

These codes were read off of my OBD II reader and then cleared after,P1123 and P1125. I have driven the car for 100 miles since I cleared it and the light has not come back on. The car was hesitating when I went to gun it while the CEL light was on,and it still hesitates rarely after I cleared the CEL light. It does not hesitate often,its rare,I'd say once every 50 miles. Iam planning on attempting to clean my MAF on Wed. hoping that it cleares the issue up,at that time I will take a look at my K & N air filter to see what shape that is in. If that does not work I will order a new MAF(non e-gas,$246.77 from ******************************** Arizona) anyway because mine has 53,000 on it and I have heard that they can be faulty.
Here is a link to the MAF I will order if needed,is this a good price? ( I beleive it is the top one)
http://www.************************************************************/search/productx.aspx?sid=n0e5sy55lmshgzvjglb1gr45&makeid= 800019@Porsche&modelid=1357196@BOXSTER%20&year=199 9&cid=22@Fuel%20%26%20Air%20System&gid=5068@Air%20 Mass%20Sensor
and if I must order the new MAF I will install a Mahle Air Filter as well instead of re-oiling the K & N.
If I redo the MAF and air filter and the problem is still there what else could it be?

Sounds like you are on the right track. The K&N filters have a tendancy to kill the mafs, but it is usually after the 1st install, or after the owner has oiled the filter. The hesitation sounds like a maf sensor. I would go back to the stock paper filter like you mentioned. K&N filters are great filters.....just not on the porsche's with the overly sensitive mafs :)