thanks, I will go with existing install since I have paypal on my website, hope my understanding is right, however when I Modifying tpl_shopping_cart_default.php
i get this fail message, althgouh I can see the line I added.

open tpl_shopping_cart_default.php failed: Permission denied at cpanel line 4988
Carp::croak('open tpl_shopping_cart_default.php failed: Permission denied') called at /usr/local/cpanel/Cpanel/Fileman.pm line 1105
Cpanel::Fileman::fmsavefile('%2fhome%2fisparkli%2fpublic_html%2fincludes%2ftempl ates%2ftempla...', 'tpl_shopping_cart_default.php', '<?php^M^J/**^M^J * Page Template^M^J *^M^J * Loaded automatically by ind...', 1, 1) called at cpanel line 4988
main::__ANON__('%2fhome%2fisparkli%2fpublic_html%2fincludes%2ftemplates%2ftempla ...', 'tpl_shopping_cart_default.php', '<?php^M^J/**^M^J * Page Template^M^J *^M^J * Loaded automatically by ind...', 1, 1) called at cpanel line 1093
eval {...} called at cpanel line 1093
main::real_exectag('<cpanel Fileman="fmsavefile($FORM{\'dir\'},$FORM{\'file\'},$FORM...') called at cpanel line 4015
main::dotag_finished_headers('<cpanel Fileman="fmsavefile($FORM{\'dir\'},$FORM{\'file\'},$FORM...', 0) called at cpanel line 3898
main::cpanel_parseblock('<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"^J^I...') called at cpanel line 3842
main::cpanel_parse('GLOB(0x8fade8c)') called at cpanel line 5331
main::run_standard_mode() called at cpanel line 387